Well, I don't know about under $800 but having a lot of the under $500 compressors (alesis, DBX, behringer) I have fallen in love with the ART TCS.
I'm sure the guys here will direct you to something better if you can go $800 but for that much you can buy two of these and have four channels of compression.
You can read what makes it special online, but needless to say there is no other compressor I am aware of which gives you that kind of sound, with both optical and VCA-type compression at that price. I doin't know why they stopped making them, but it sounds amazing.
Find one used on ebay.