Thinking of buying a SD-50 (have downloaded all the user manuals from roland website and compared) - anyone got a patch map for it?

What I learnt:

SD-50 - midi module plus usb midi/wav/mp3 player. You can send midi messages to it whilst the usb player is playing - handy if you want to play e.g. a melody line over backing tracks. Can also alter key and tempo. Sounds right for me as I play keyboards in a couple of bands and also do gigs with a sax player where I have done all the backing tracks via BIAB.

Sonic Cell - midi module plus usb midi/wav/mp3 player. Says you can't send midi to it whilst usb player is playing. "Input/output of USB audio and MIDI messages cannot be used at the same time that the SMF/Audio File Player is playing". No key change. Lots of effects and expandable - designed for those who like tweaking sounds. Probably better sounds than SD-50???

BK-7M - midi module plus usb midi/wav/mp3 player plus accompaniment. Last part is like on many keyboards - you choose what style and it reacts to the chords you play, but you can at least set up lots of parameters beforehand and trigger changes with one button. Can't really see the point if you have BIA, where you can drive either of the two above direct from laptop or store midi files on USB stick and play those. I suppose you could argue that the backing will not be so rigid, and you can pop in another verse or chorus if you feel like it, but you're still going to have play all the chords in your left hand (piano/keyboard) and whilst that may be good for e.g. jazz, not so sure it's how I want to play other stuff.

Please shout if you've got one of the above and I've got it wrong or have missed something important!!?? Hope to get down the music store and try them all out soon.