Looking for a longer blade length in an every day task knife, I got the Stretch and the Manix 2 LW for comparison. I've included the Delica 4 in the photos to give an idea of the relative sizes involved. The Stretch and the Manix are similar sized knives overall. As you can see they are significantly larger than the Delica especially where the handle ergonomics are concerned. Compared to each other the differences are mainly:
Blade shape: both knives have full flat grind blades and their overall blade length and cutting edge length are close enough to not make much of a difference, but the blade shapes are almost diametrically opposite for Spyderco designs. The Manix has, of course a classic leaf shape which I like in a smaller knife like the Dragonfly 2, but think is not as useful in a larger blade. This is because the leaf shape results in a very wide blade, when over about 3" in length. For many uses this doesn't matter, but for slicing anything wide, especially something wet or clingy, the material tends to adhere to the blade's wide surface area. The Stretch by comparison has a much narrower blade height by design, which offers less surface area to those clingy bits.
Also, notice the continuously curved edge on the Manix. The Stretch has a long straight edge sweeping up into a belly near the point. This makes slicing meat, cheese, potatoes, etc. easier with the Stretch than the Manix.
Blade Steel: The Manix 2 LW uses BD-1 Carpenter steel. The Stretch's blade is VG-10, a Seki-City, Japan standard for Spyderco knives. I am no steel expert nor even very knowledgeable about blade steels, but I suspect these two steels are very similar in their ability to be easily sharpened (in contrast to some of the so-called "super steels"), retain a sharp edge during normal use and are rust resistant. To my knowledge, there isn't much of significance to choose from with these two steels.
Choil: The Manix does have a very obvious, deep and well executed jimped choil for one's forefinger should you need to "choke up" on the blade. The Stretch has a nod toward a full choil, which, strangely enough seems to be just enough. There is jimping on the Stretch's ricasso and just a bit of rounding in that area with the handle so that choking up here is also reasonably comfortable and works well for increased leverage, and to discourage one's finger from slipping forward onto the blade. It is sort of a hybrid choil-casso as one finds on the Delica (but without the jimping.)
I love the choil on the Manix except when I'm at the chopping or cutting board, then the rear of the coil nearest the handle where the metal protrudes downward a bit tends to hang up on the cutting surface. I can slice stuff like onions, carrots, etc. more quickly and with no hangup using the Stretch, but not so easily with the Manix.
Lock: Here are two very different and distinct design philosophies at work. I don't know, but I think Sal designed the lock back and Eric the ball bearing lock. Now, I confess a preference for Spyderco lock back designs. I find them simple, strong, secure and easy to operate with either hand. Done correctly, the lock back knives can be closed with one hand, either left or right, with no danger of swinging the blade closed on a finger. The same is true for the Manix' clever lock release that requires two fingers in a one-handed grip which also positions your fingers out of harm's way. It is a bit easier for me to operate the lock back with one hand because I'm used to it. I'm sure with time, I will be as at ease with the ball bearing as with the lock back. Under normal use, even heavy normal use, I would expect both locks to be secure.
Handle ergonomics: These are also dissimilar to each other. One of the Manix claims to fame is its light weight. Mine weighs, on the digital scale, 2.9 oz., the Stretch comes in at 3.2 oz. That's 3/10ths of an ounce difference, which really isn't all that much. The difference might be perceivable if you think about it while holding the knives, but otherwise it is a very small deal indeed. My iPhone 6, naked, weighs 4.6 oz. and no one complains about how heavy their iPhone is.
But, the big differences in the handles are the widths and shapes. Simply put, the Manix handle is blocky, wide and with abrupt corners. It fit the hand well whether choked up or not and I could easily use it for an extended period of hard cutting without suffering damage. I might feel hot spots and the edges under very hard use, but, again, unless one is using the knife hard all day it's not a big deal. If one needed to use a knife that hard, neither the Manix or Stretch would be your best choice.
The Manix's wide, but very comfortable handle made from FRCP (fiberglass reinforced co-polymer), coupled with it's extraordinary light weight pushes the top of the acceptable handle size. You wouldn't want to go any bigger, but with the Manix's combination of blade length, shape and handle ergos, you would not need to.
An aside here about the Manix 2 LW's handle and certain knife reviewers. I've seen and read a few so-called reviews by people who moan loudly about how terrible the Manix 2 LW's handle is. They must have some kind of obsessive disorder because there is absolutely nothing "terrible" about the handle or design. How a handle feels and works is heavily a subjective opinion and I suspect these reviewers needed to find something to complain about in order to set them apart from the mostly positive reviews of this knife. You may or may not find the Manix 2 LW's handle to your liking, but it's far from terrible.
The Stretch's handle is the tried and true fiberglass reinforced nylon (FRN) that Spyderco has been using for some time. Light, strong, high friction, colorful, FRN has many attributes and many supporters, myself among them. Beauty is still in the eye of the beholder, and while some may not like the looks of FRN, I do. More of a 'form follows function' approach.
The Stretch's handle is similar to the Delica's handle but since the same size hand will grasp a bigger handle somewhat differently than a smaller one, the shape has been designed to accommodate that. In some ways it is sort of "melted", in that the edges, contours and bumps are rounded to fit the hand's contours. And, it feels bigger. It isn't, but because of the way the hand and handle contours and size meet, it feels like it was made for the hand.
Clip: Finally the clips. I like and dislike pocket clips on knives. Small knives can work well in-pocket without a clip. Larger folders, like these two, really need either a clip or a sheath. I carried an old Buck Ranger in a leather sheath I made to be a snug fit but an easy release. I like it, still have it, and often think about going back to a sheath for my bigger folders like the Stretch. Why? I think the ergonomics and comfort of a good handle are spoiled by the damn clip sticking out along the side. But, there are times when I don't want to strap on a sheath and knife and would rather put the knife in my pocket. If it is too large for that, and I think these two knives are, then they need a clip to keep them in place and not take up all that pocket real estate otherwise. So...
I am still on the fence concerning wire clips. I have found that shorter ones, short by necessity to fit the handles of smaller knives, may tend to bend and distort when caught on something while clipped to a pocket, while a longer wire clip is more likely to spring out and back into shape. Care must be taken to design a secure means to attach the clip to the scale, and it must be removable and reposition-able by by the knife's owner and resist damage to the scales under stress or sudden pressure. The stamped clips are probably more secure, although a long enough wire clip to incorporate some spring when pressured may be just as secure. Jury is out right now on that.
Wire is nice when it blends in with your clothing and it does't scream "knife" like some stamped clips do. So, pick your clip poison with these knives. It is always possible to get an after-market clip of your choice if you don't like the one that comes with your knife. And a nice leather sheath too.
The Manix 2 LW is an up to date locking folder that incorporates extremely light weight for its size, outstanding blade steel, a strong and innovative lock, thoughtful ergonomics and quality construction at a price that won't break the bank. The Stretch is a product of a long design evolution by Spyderco following a different design philosophy. It is not as innovative as the Manix 2 LW, but for my uses, I think it is a bit better. Now, as the saying goes, your mileage may vary, which is a good thing. You really can't go wrong with either knife.