Actually, I tried both (CD and PSM), and at least for me, the CD loading seems to be quite minimal for battle encounters - I found it bearable, so I left it on CD music. But yeah, PCM isn't bad either. The last few RPGs I've played all had this option, which is nice (DSI & II, Gulliver Boy, Beast Sanjuushi).
I'm about 5-6 hours into Dragon Slayer II, and holy cow, this one is soooooo sloooooow compared to part I. The game is super-stingy with giving you exp and gold. In fact, I find that I continually have to sell all the stuff I find in battle to make ends meet (buying weapons & armor). I swear, I think about 90% of gameplay so far for me has been just trying to level up my character. I'll probably need to increase exp for
another hour or two to continue on with the game...