Yeah timmymac, good choice indeed, going the pre-owned route
I went round and round with this just recently, and heard enough comparisons to make me not want to listen anymore..ha!
I really liked the sound of the Apogee stuff like the symphony, but that would have destroyed my budget having to switch over to a mac, and buy more pre's.
The converters in my 003 were very flat and lifeless sounding to my ears, so I had to do something.
The Apollo seemed the smartest choice for being able to both stretch my budget, and having better sounding converters (too my ears)
I listened to clips done with an Apollo vs a Symphony and DID like the Apogee better, but the Apollo was "close enough" for me to finally make my choice.