Depends on your personal preference. They're both top drawer knives, and the feature sets, quality, and Spyderco customer service will make you happy either way.
Personally, I carry the Wegner much more often. It's a lot more comfortable to work hard, and it's got a heavy, "warm" feeling that makes it a very satisfying knife to use, or even just hold. The Starmate is all that and a bag of chips as well, and it's straighter lines and sharper corners make it a sleeker, sexier knife. 440V is a beautiful thing, too.
I like and carry both knives, but I'm a Wegner "fan". I bought a Wegner Mouse. I bought a custom Wegner fixed blade. I felt compelled to find and meet Tim Wegner at the Blade Show. Not a lot of knife designs have inspired me to become so devoted.
Pop over to the Spyderco forum for this thread:
Another Wegner Spyder Bite
Again, the Starmate is a superb knife too, but it doesn't inspire zealotry like the Wegner.