I just wanted to chime in and express how interesting and exciting HomeKit integration would be.
I know Smartthings has modified a lot of things to be compatible with Nest. I hope they would take a second look at HomeKit and see what would be necessary. Nest has the Google Now integration that was recently released. It would be cool to control Smartthings with Siri.
The data retention and use restrictions with HomeKit mostly pertain to the misuse and mining of data (especially for commercial purposes). It also restricts what data Smartthings can pull from Apple without abusing it (data from iPhones)- which is reasonable considering that we’re dealing with people’s homes, locations, locks, etc. I would be worried if Smartthings was not complying with basic data security! With the changes made to Smartthings own data retention (down to 7 days, etc) to comply with Nest requirements, I’m sure they are likely to already meet most of the requirements.
It’s still early in the game, but I hope the fine folks at Smartthings don’t discount Apple’s HomeKit too easily.