The compression takes longer than other software (ffmpegx), but works okay.
I can't get it to burn a DVD+R worth a damn though, but it might just be my shoddy DVD burner. Haven't tried -R, so can't say anything about that. And dual-layer media is too expensive compared to 2 DVD+/-Rs.
CDs burn great, no complaints there.
And the mount ISO as physical CD function is awesome.