I am personally a big fan of PSP Audioware and this is an absolutely brilliant reverb and definite MUST HAVE! Reverbs are a tricky subject, and are notoriously difficult to learn at the very first glance, but this, is in it's simplicity, is almost perfect.
I use this reverb a lot for opening up synth leads and with its ease of use means I can throw it onto the track and get the results I want in an instant. It works by inputting the acoustic sound space 'model' then having two main knobs of time and damp, and also a wet/dry knob. Although admittedly the acoustic spaces are not that accurate to what they are modeled on, but they are nonetheless good quality and can suit almost any material.
It has this unique ability to open up guitars and vocals without sounding 'metallic' or 'fake' like on some of the other reverbs I have heard before and the plate and spring algorithms are beautifully vintage sounding. I personally am no expert in pre-delay and diffusion characteristics so naturally I chose this and I was not disappointed one bit.
It is also extremely small in size which has HUGE advantages over convolution reverb which requires huge amounts of IR files so its quick and detailed and changing through presets causes no delay or glitching. Easy to use, beautiful trails and extremely efficient CPU usage even when thrown onto 4 simultaneous guitar parts, vocals, 5 backing vocalists, synth lead, snare and synth drums. For this price it is so very nearly perfect.
The only gripe I have with it, would be that I would have preferred a few more algorithms and perhaps another EQ knob for a truly gorgeous vintage sound but otherwise genuinely brilliant.