I have an Acer 8432 and have been quite satisfied with it. Properly configured, I haven't burned any coasters and my one experience with support was a breeze. They answered the phone fast, gave me the address to their Taiwan web site to get a firmware upgrade I needed and through the whole call, never even asked me for a serial number, etc. to verify that I owned and Acer. (After dealing with Compaq with my first computer, theis wasa switch.)
Red Book spec for audio CDs is to burn masters at no more than 2X. I haven't had much trouble with higher speed copies, but it seems that the media quality is a factor in audio quality.
My 1/50th of a dollar.