I have only one and it's like the D2 unit pictured above. It's a knife with a large
following. However, I'm not a big fan and don't carry mine often.
Clipped in pocket my D2 has a rather annoying pointed edge that if your diving for something inside your pocket and it's not the knife it's a bother. I've tried smoothing it over but it's still a bit annoying. I probably will not buy another knife with a compression lock. I don't like a lock on the top, it's awkward for me to depress it with my index finger then flick it shut.
The blade is a wee bit short but is a great slicer, and the handle fits my hand quite well. It's a very smooth opening knife as well.
I have a small modest collection of Spydie's and love pretty much most but this one like
I say is least carried.
My Military's though... that's a different story all together. Those are great!