yes, highly compressed mp3's can be lossy. but purchased ones aren't, that I have ever experienced, in any case. it's the folks that rip their own and want to make them tiny as possible that get into the loss-ness. i have loads of music and rips in mp3, and all sound great, at any level. When I buy or rip lectures, however, i may compress them a whole lot more than music.
The sansa gives the option of two modes of operation as well. one is straight USB and this is my personal preference, to know what get's copied and to what folder, because I put it there!. something you can not do with an Apple. (it does have the sync mode too, and can be made ignorant-user-friendly).
with that said, I do have a MS zune. which, like the apple has it's own proprietary software that you have to use. bah. i don't like it, but it has a 120 Gig storage, and is perfect for what I like to use it for. In fact, I don't use it to listen to the Bible any more. I have dedicated mp3 players for that now. one for each version, so that I can just pick up the one I want and hit play.
it's all personal preference.