You may want to consider the Electrocmpanient EMC-1. I am not sure, but I suspect, that you can find one (used) in your price range. Personnaly I liked it better than the Audio Aero because of its seemingly better build quality. Sound wise they sounded different but I can not say one was better than the other; just different. The Cary is very good as well and it's build quality appeared to be good.
As Jtinn suggested you can run it directly into your amp because of it's variable output capability; but I felt it sounded better running through my preamp.
In the end this is all just opinions and other peoples experiences, you really need to listen to them yourself. My experiences have born out that there are not huge differences between any of them sound wise. But out of all the one box players I have heard, I liked the Accupahse DP75V the best. Good Luck!