Well lossless is much larger than MP3, the file sizes vary, if a 5 min song makes a 50MB WAV, then it'll be about 25-32MB in Lossless, The time it takes to trancode I'd say is just as long as ripping from a CD and encoding on the fly. But it does take a little longer to transfer to the D2 (I think thats the bottle neck). 5-6 min.
The only problem I'm running into is with the Tag info. My WMAL rips have an Album Artist field and embeded album art. The D2 does not handle the Album Artist field correctled with FLAC (it makes it show (Artist=????), and it only recogizes album art by a cover.jpg in the directory. So I still have to make some changes. But its not such as big deal since MediaMonkey lets you edit the file tags in batches.