I've bought and sold 2 Resolution Audio Opus 21's here on AudiogoN. I wish I had kept one. They are really good CD players for the price and they are backed by an excellent company. Also, I think the Opus 21 uses a CD-ROM drive for transport, so a new drive could likely by specified by RA if the current drive becomes unavailable. Check with RA regarding the type of transport used if it concerns you. They are good folks and will likely be happy to answer your questions.
Enjoy,
TIC