I'm making no excuses for his results - he usually gets the job done in impressive fashion. I like watching him fight because he's an odd character whose the best threat to the best fighter in the world. As for what he does in the cage, he's not overly creative or exciting. He's GSP, he's Fitch, he's a grinder to the highest degree and there's nothing wrong with that.
The ONLY huge problem with Sonnen I have is what he's done in the Filho and Silva fights where he's tried to make a mockery of the sport by tapping then acting like he didn't. Silva tapping Sonnen is one of the greatest moments in the sport, but its partially ruined by Sonnen's act.