I have 3 different models:
SwissCard: not recommended. The blade is tiny. You're better off getting a swiss army knife, which features the same tools, but a bigger (normal) sized blade.
Spydercard: Its a Spyderco, so the quality is good. Sturdy build, strong lockup, and razor sharp. But the blade is an awkward shape, with no real point. And its a bit heavy. It is discontinued as far as I know.
SOG Access card 2.0: the Winner! Here is the review I did for it a while ago in another thread:
"I was worried it might be flimsy based on pictures, but its not. It is solid. It locks open solidly, no blade play at all and the handle doesn’t have any ‘give’ when squeezed either. (Warning to lefties: the axis lock is not ambidextrous like on a Griptillain.)
It opens buttery smooth with the thumb-slot or flips open lightning fast if you disengage the axis lock.
I normally don’t like handles with finger grooves, but here I find them useful since the handle is so thin. They give you a more secure grip. People with big hands: this knife may get “lost” in your palm, but that is true for any knife this size.
When I ran my thumb across it, it did not feel especially sharp, yet it cuts beautifully! I can’t figure this out. Maybe it’s the grind? Or maybe you just can’t go wrong with VG-10. Whatever the case, it is sharper than it feels, if that makes sense.
So far, I have had no wear on the coating, but I have only had it for a few weeks.
This is one of those little knives that you truly don’t notice its in your pocket until you need it. Very light, very thin, you forget you are carrying it! It is a futuristic looking gentlemen’s knife, and a quality piece. I don’t know if its worth $100, but I found mine under $60, and at that price I am very satisfied."