I could buy either or both, and I'm only buying a DI.
The way I look at it, DI is just a blast and reminds me of the later years B/W games, you know, full featured, fun games, but DI has even better code and all the modern upgrades. Some of you that are bashing the theme, well some of the best games to me are unique themes (Whitewater, AFM, MM, TOTAN, TOM, CV, the list goes on).
If you think about it, DI is selling very well even though a lot of people hated the theme.... imagine if JJP had released DI on the exact same playfield as Star Wars (sparse) with the exact toys modified to fit DI, ie, a crappy clam-shell toy, a toy on a stick (IE Tie fighter), etc., you wouldn't give the game a second look. The only reason some are giving Star Wars a first or second look is ON THEME ALONE. That doesn't do it for me now.
Star Wars is absolutely a dream theme for me, and I was excited to hear Stern was doing it, but I'm just not excited about what I see. Sure I may own one down the road, but as a previous owner of early code-starved pins that were extremely slow to upgrade (most notably, but not limited to, Kiss and X-men), I'm out on this one for now.