I would love to see data that supports this. Most GM VCM’s are extremely open. I don’t know of a single feature that it doesn’t have that I would desire (especially when you consider a custom OS).
I will admit that my tuning has been limited to eManage, crome, crome pro, hondata, HP tuners and flashpro, but out of any of them HP tuners is by far the most in depth. Most of others have such horribly generic tables and options that I feel like I’m playing with a Fisher-Price product.