With Lunar 2 I havent seen that many problems with the ISO/MP3 versions. After all, it only has 2 audio tracks (I have the original disc right here). The rest of the audio is all in the data track. Lunar 2 also compresses well.
Lunar 1 is the one where ive had issues finding a good ISO/MP3 rip. It has like 50 some audio tracks. Sometimes I've seen tracks all mixed up in the wrong order or missing mp3s, or it'd freeze right around the main screen that says Lunar The Silver Star, and with one rip it died as soon as you talk to Ramus. I know there are working rips out there, but I eventually bought it (again) off ebay for a spectacular price (like 17 bucks including shipping), and the disc/case was mint (manual was waterdamaged).