I went with COBB. I felt more comfortable heavily modding my car with a flash based tune that would alter fueling tables & cam timing. I also liked the simplicity of data logging & fault code reading with the COBB AccessPORT. I haven't been disappointed with the performance & love the results (160 WHP/170 WTQ gains over Stock Tune).
http://www.e90post.com/forums/showthread.php?t=778331