[Kamal]

Definitely a question that can get personal and turn into a flame war (especially on E90post). The real answer depends on what you want... everyone will vouch for the tune that they're running. When running a tuned car you WILL get better performance, you will generate alot more heat, and you may run into issues as the greater power will expose components that may be on the fringe but not stressed on the factory tune (in most cases people quickly realize that their HPFP is failing after a tune). All three of the big players here have proven long-term reliability and great customer service.

That said, I vote for the Cobb tune. Easiest install/uninstall, updatable for life, flash-based tune, handheld diagnostic and data logging/monitoring features.