I've been through pretty much all of them (save for a few, like the Spaceman spring reverb in a pedal thing), and I find the Neunaber stuff to be really excellent. If you get a Stereo V2 version (Slate, Wet, etc.) you can load any Neunaber Expanse algorithm. What I like to do is run the "Infinity Hold w/ Reverb" algo, which means that the Wet reverb is always on but when you engage the footswitch it holds the signal like an EHX freeze. This is a lot of bang for the buck, when you think about it. If you add the EXP footswitch you toggle between four algos w/ two presets each, so you can have multiple reverbs or add delay, chorus, trem, etc. if you like.