Looked into some of these myself recently -- I'd be all about the Feedback Modules one, I had an FM module a while back and was pleasantly surprised by how high quality the thing was, and the price is not bad at all -- but it was just too big for my system. So I went first with a Blue Lantern Sir-Mix-A-Lot (the full size one) and then more recently the Cosmotronic Cosmix you have pictured.
The Sir-Mix-A-Lot was actually pretty great -- six channels, two stereo aux send/returns, applicable per channel with global attenuators as well, mute switches -- it's a great bang for the buck. Couldn't really be overdriven, but I never noticed any channel bleed or anything like that; enjoyed my time with it.
However, it is also an extremely cramped panel/UI and was cutting into precious HP, so when I found a good deal on a Cosmix I traded for that. The good: much cleaner UI/panel layout -- it's nice to be able to just visually see where the sliders are at, vs. a bunch of same-y knobs; clickless mute switches (I didn't notice much clicking on the BL mute switches either, but the Cosmix are definitely true clickless); optional "drive" for a little more saturated gain/color; good sound quality and handles overdrive better than the BL; two stereo inputs. The bad: I really do miss the dual aux stereo send/returns on the Sir-Mix-A-Lot, especially as I have more and more stereo modules. The Cosmix has one mono aux out only. If that doesn't bother you though, it's a solid pick.