I've always loved Spydercos initially, especially the Endura, of which I was a really big fan of in the early 90s. But then they all developped vertical blade play over time, like most soft-pinned lockbacks... Some of them are tight in a way that will last, but you have to find a rare one like that among many, and the non-removeable soft steel pins doom these knives to looseness in the long run... So for lockbacks, Spydercos are consistently not really tight, and this goes all the way up to their high-end lockback Civilian...
When the Military first appeared around the mid 90s, I thought the liner lock would forever solve the tightness problems, instead I got what I think is one of the most ill-conceived knife I have ever seen: The handle screws screwed directly into friable G-10 handle slabs holes!!!!!!!!
When I tested disassembly, the screws just tore out the G-10's holes, these of course being utterly devoid of metal to metal contact, and the knife was instantly ruined...
Also its liner lock was thin and not confidence-inspiring: Probably both issues have been improved since, but this is a model that left a further bad taste...
Then I got what I still think is the greatest folding knife design ever (but not really as a user): The Spyderco Civilian. The aluminium handle model I got was vertically tight (I had given written instructions to the "Golden Edge" store staff on how to pick the tightest one out of several they had), but the pivot pin was, as usual, made of some extremely soft metal: I knew I could not ask much of it, but I still successfully improved lateral rigidity with light hammering of that soft pin's extremities (the knife became a bit harder to open, but that eased with oil and over time).
After 4 years the knife developped a slight vertical play (not from use, just opening), and I solved that by sawing a deep centered longitunal notch into the lock bar, and twisting a flat piece of brass into the notch and then down into the lock to improve vertical rigidity: Amazingly, this was completely successful and the knife remained perfectly tight over the next 12 years until I lost it from a jacket pocket while running (to my great chagrin).
I immediately had to get another one, as they were now made with G-10 handles and the horrible soft pivot pin was replaced by a far more serious and much bigger pivot pin machined in hard metal, not some nail-marking white metal tin rod (I'm exaggerating, but only slightly)... Since I knew Spydercos were haphazard about vertical rigidity, I gambled on buying TWO Civilians and getting rid of the looser one...: To my ever lasting joy, one of them was the tighest lockback I have ever seen (fully a match to the best of liner locks), and the other was loose as usual, so I happily sold it, and now greatly enjoy my only folder, having since lost interest in folders in favour of fixed blades... (I prefer the Civilian being a lockback, as the lack of closing tension in liner locks resulted in a serious hand injury for me on a CRKT Apache)
Around 2003 I had got the plain edge bowie version of the Cold Steel "Prolite" range, and I found its sturdy "thumb shelved" liner made it the best liner lock action I had seen then or since. I also found the oval opening hole ergonomically superior to the Spyderco round hole. The knife was generally better in design and construction to most Spydercos I had owned (if a little strange-looking), but for some reason I coud not re-sharpen the deeply curved edge without rolling it in the middle, a peculiar issue maybe due to my free-hand sharpening inexperience... I have bought many Spydercos and found this one Cold Steel folder more useful and impressive, but still prefer the "feel" of the Civilian to anything else, even though it is not really for everyday use (or any use at all other than defense really)...
I remember getting the much-hyped AFCK back in the mid-90s, and that one could unseat the liner lock through handle flexing just by slight squeezing hand pressure: Though I am against typecasting by brand, I don't think I ever got another Benchmade...
Edge-holding wise I found all the Spydercos wearing in a sound way, and fair to sharpen, while Benchmade's ATS-34 had a definite chipping tendency. Cold Steel's Prolites seemed hard to sharpen without getting endless wire edges, though I may better at getting rid of those now...
Gaston