I've been looking into getting one. Not going to lie...I cant afford most of the DS games I want and it would be nice to be able to play them anyway...at least until the price drops or I can get cheaper used copies. Plus, some games are impossible to find (Electroplankton and Advance Wars DS come to mind). Add in the homebrew scene (I found a port of Dungeon Crawl...so awesome), and it seems like the $40 investment wouldn't be a bad idea.
So, anyone use one? I hear the "R4DS" is the best one to get right now.