I had the HMI unlocked and BCM spec programming done on my 2016 Yukon XL Denali. I can't say enough about the support through this process. Chris answered all my questions (and I had a fair amount) without hesitation and no delay. They performed the work and had a quick tun around on both modules. Everything worked as expected and couldn't have been easier. I now have the unlocked HMI... mainly for the video in motion function for watching the fire tv, etc. The BCM spec programming is pretty cool as well. mainly for me was having a legit capability to have the fogs on with highs as well as the intellibeam still being functional. It's nice to be able to vent the windows as well with the key fob. Overall... I couldn't be happier. Top notch service and communication from start to finish. Now I just need to figure out getting the wire powered so I can turn on the backup camera while in motion.
If it's something you're on the fence about... do it! I know Pgamboa did an in depth review however, feel free to ping me with any questions.