Jonathan, the 'C515 is an older model. It was once part of Sony's "mass-market" line, as opposed to its ES line. I'm not trying to sound elitist, but it is an honest statement. The 'C515 would have been found at Best Buy, Circuit City, Sears or the equivalent when it was a current model. Generally speaking, Sony makes a good budget CD changer. However, for around $300, you can get a better CD player than the 'C515. Of course, free is free.
Yes, free is free, much better than ANY other CD player in my opinion. I didn't exprect it to be that great, but I new have a CD player, before I didn't, and I'd free. I may replace it in a couple years, when it dies on me.
I have a Sony C50 5 disc CD player and although I'm aware its not new, its 14 years old, it still sounds ok. I guess newer stuff might sound better, but it still works for me.