Sorry for the late reply!
First, let me clarify. I have 4 PM2's and they're not going anywhere. I carry one IWB at work (with something smaller RFP) 2 or 3 times a week. The other days I usually have a Manix 2 LW.
Regarding the Sliverax. I think I like it so much because it's design is so different than everthing else I have. I like that! The ergos work well for me but I'm sure it doesn't work for everybody. Like I said previously, I like the thin profile, wire clip, blade shape, longer cutting edge. The action on mine is crazy smooth. It's even better than my Sage 3 and that's sayin' a lot. But it wasn't quite as nice out of the box as it is now. I did a little tuning and, combined with several months of break in time, it's become even better.
Let me be clear. I'm not trying to talk you into buying a Sliverax over a PM2. There's a reason the PM2 is so iconic. If you don't have one yet you need one. Maybe try a Sliverax someday down the road and see what you think. I was skeptical about it at first and now I'm really glad I tried one.
Caly 3.5 is a fine choice too. I also have one of those and it's not going anywhere either. The Mantra's another good one. Basically a Delica on steriods. Lot's of blade & cutting edge in a relatively small package. The Mantra 3 should be out soon and it'll have some of the same features the Sliverax has. Compression lock flipper with the new bearing system, wire clip, carbon fiber-G10 laminate scales. Should be a good one in my book.
I see a lot of threads & posts where someone is wanting to know which knife is better A or B. I always have a difficult time choosing one over another. Spyderco has so many good designs and which one is the best really comes down to personal preference. As the saying goes...they're all good, just different.