The SmartBoy is a USB device, while the GB Transferer you linked to is a Parallel Port device (with a USB plug only for power it seems).
The GB Transferer looks like a clone of BUNG's GB Xchanger so it probably uses the same or similar software, and because it's parallel you can only use it on a machine that's running XP and has a parallel port (it seems unlikely that any modern Mac would have a parallel port). It can also work on both GB and GBA games it seems.
The Smart GB works on my Windows 7 computer and should work on all Windows OSs. As for Mac, I don't think they released any software for Macs. The Smart GB is only for GB games; it has no GBA support.
By Smart GB do you mean SmartBoy? And by GB games do you mean to include GBC as well? How well does it read and write saves to and from original cartridges?
http://smartboy.ugu.pl/ hasn't been accepting orders since the end of last year, and its forums are down, but if I could get a hold of a SmartBoy and find an additional solution specifically for compatibility with all the GBA save types I'd be golden. Maybe if one day I developed the technical prowess I'd be able to port whatever software I need to work with.
QUOTE(thaddius @ May 17 2011, 02:54 PM) If you have a DS or DS Lite and a flash cart then you won't need a product that can back up GBA saves because you already have one.