I've got one of these and I absolutely love it. This is my usual backpacking knife. The blade is big enough for anything you might normally need, and then some, and the locking mechanism is as sturdy and reliable as they come. It also has a very strong detent so the blade will not accidentally open and cut you (better than the Griptilian in this sense).
I have never felt like this knife is weak, but I have never torqued or pried with it. The blade is much thinner than that of the other, heavier Manix models. The plastic handles do have slight flex if you squeeze them hard but no lateral flex at all.
However if you have corrosive sweat or live in a humid environment you may wish to check out the Salt series- less sexy but 100% rust-proof. Since the Manix 2 Lightweight cannot be taken apart, you may find it difficult to polish off rust if you do get any.
I own more than a few knives and this one sees regular pocket time.