I own both, and can't suggest either. Star Hogs gets pretty old mid-way through the campaign. I also found the graphic style was rather ugly. After playing through the campaign when it was only 16 levels, I had no urge to go back through it. So, final opinion: no replay value. Worms I first played on 3G, and it performed very poorly. I upgraded to the iPhone 4 when it was released and tried it again, and it failed to grip my attention. Unfortunately, the two games combined diminished my interest in the genre, so I didn't try any others, so I wouldn't be able to recommend anything... so I'm not much help for your decision, but maybe I'll save you a few bucks, instead.
I haven't played Worms (on the iPhone, at least), but I can say that Star Hogs is a great game. The amount of customization is just... mind-blowing.
Actually, I'm glad to see this thread arise from the depths. I've become interested in these type of games after trying out Stone Wars. Glad to see some additional info/impressions and link on other same type games. .
