Im not saying one is better than the other (thought I have my preference) I'm just saying that Kershaw has such a variety that seems to defy the standard knife, while still retaining everyday usability (I know it's odd looking, but that dodo doesn't appear to have much conventional usability). It's thew new and totally different that's a big draw, unless I'm mistaken, all the knives shown in spyderco's lineup are frame/liner lock (balisongs excepted), while kershaw has the stud, ET lock (that is off is who knows what category), and hawk lock. The blade shapes are fascinating, and still 100% usable.
Different isn't necessarily better. Spyderco produces many, many "leaf shaped" fully flat ground blades. I love this blade profile for general cutting. Their "Captain" model is "different," but I did not find it nearly as useful as their more conventional blades. It depends on the work the person performs with his EDC though. Certain types of cuts are better done by a serrated hawkbill, others a drop point with lots of belly, some a small wharncliffe excels. The Dodo for instance would be exceptional for opening packages of all sorts, cutting up cardboard etc, but it would make a horrendous paring knife. Different, in my eyes, is only good if it improves upon the conventional. Recurves are different. Many people find them useful. I did at certain times, but overall I'm happier with the profile of a Junkyard Dawg. I can recognize why others would like them though.
Spyderco has a few locks they've developed themselves actually. They utilize the following:
Front lock (Lockback placed in a position to make one handed closing possible. They execute these very, very well, to the point where many Spyderco fans are reluctant to ever go back to liner locks. It's kind of funny, I've seen some Kershaw fans not want to use a Spyder because it's not AO and I've read of Spyderco fans not wanting to use a Kershaw because it's a liner lock.)
Compression Lock (A unique twist on the liner lock concept that dramatically increases strength, though closing the knife can take getting used to at first. The release is on the top of the handle and the liner engages the tang in a way that creates a much more secure lock)
Ball Lock (Sort of like an improved version of Benchmades Axis Lock. They have two versions of this lock, caged and non-caged)
Liner Lock (They radius the tang on many knives where the liner engages, which is seen by many as a smart engineering choice. Their Military model, like a lot of Kershaws well-executed liner locks, has converted many people who lacked faith in LL's previously)
Frame Lock
Notch Joint (A hybrid between a lock back and slipjoint. It operates like a slipjoint but has a slight notch resembling a lockback which makes the knife require much more force to close than a regular slipjoint)
They've used a few other locks over the years like the Phantom Lock I believe it was called on the Meerkat model. Not only do they offer a good variety of lock types, but they're generally extremely reliable, secure locks.
Spyderco and Kershaw are two of the best production knife companies I've come across for a modern one handed knife. They both create a wide variety of knives, from kitchen knives, small and large tacticals and traditional / modern hybrids like the double cross or micro dyad. Each company has knives from 20$ to 200$ that will give you years of service, and have outstanding customer service to back them up.
My preference is for Spyderco. I've tried out a lot of Kershaws, though I still haven't gotten to experience their very high end knives (Most expensive one I had was a Spec Bump), and I found the ergonomics didn't fit me quite as well as my favorite Spydercos do. I also prefer the opening hole over every other method, prefer Spydercos steel selection and clip design and generally just find their designs more appealing. Like I said though it's just my preference. I can't really say anything negative about Kershaw, my hands just like Sal's interpretation of knife ergonomics more than Ken Onions it seems.
It would be fun to see them do another collaboration model.