I had Cobb originally and sold it when I thought I was going to trade in my car. Long story short, I still have my car and have opted to go the Mountune route this time.
Couple thoughts: Mountune's quality is just as nice as Cobb's. Both are built very well. Mountune's is softer than Cobb's; vibrations were worse with the Cobb IMO. Mountune feels like stock with the AC on and when daily driving but eliminates the clunk.
Bottom line is both are very nice and I would highly recommend both. Just depends on what you are looking for.