open source software is typically hacked ecutek anyway, but the advantage of ecutek is if something happens unexpected then you (or mapper) can ring ecutek to discuss, my old hawk for example, kept getting a phantom fault code to do with MAF over volt. Was checked and totaly fine, but the code kept coming up, with opensource your stuffed, no technical backup. Phone call to ecutek and a software revision later and problem solved. I believe that revision is now part of the Ecutek software so all benefit of the upgrade. Also Ecutek software is regularly patched, updated and glitches sorted out. Opensource just doesn't get that.
At the end of the day they do the same job, but depends what you want.