WMA, is a lossless compacted (rather than lossy compressed) format -- and it is bit-by-bit true to the original. Unfortunately, the downloads from Musicgiants can't be converted to other formats without workaround.
Yes, I have tried MusicGiants, though they are delivering to the PC platform and I'm a Mac-addict. Wanted to point it out, though. There are other companies offering high-resolution downloads, and pretty soon it's going to dawn on the music companies that they can pick up the slack from their drop in CD sales by offering high-res to customers through broadband.