hmmmm...I'm really liking the locking mechanism of the Manix, and in terms of ergonomics, I'm looking for something that will feel as good as the Caly 3 in my hands.
The ergonomics on the Manix2 are great. I have medium size hands but can still get an amazing grip on the thing. Once it's locked and opened it feels like the knife version of a breaker-bar

My ONLY complaint is it's a tad bulky for slacks in the office (even tho it's deep ride clip is very discrete). I don't think it's a ton heavier than the G10 Endura just a bit wider. You have the Caly3 so that's a nice medium-duty knife.
I would argue that the M2 is a must have and one of the best values Spyderco has right now. For $60ish you can get one of the beefiest folders available anywhere so even if it's a bit large and situational, at least you don't have $200ish invested in a tankfolder.