> You get only marginal improvement in space saving with enormous increase in encoding time.
It takes about 3 seconds to encode a track to FLAC on my desktop (which is about seven years old, and not particularly powerful: Athlon II X3 450 3.2 GHz). Much less than it takes to rip, even at 30x avg CD rip speed.
If the compression is launched in parallel, using a second core, it doesn't increase the rip time.