I'd research Chilipad harder if I were in the market again. At very cursory glance it seems like less of an uphill battle. I could be wrong and they could be douchey, or their engineering somehow sucks, but maybe they are good too.
FreeSleep is what I would do if they try to force the subscription on me, but I probably wouldn't buy the product hoping that I can change their firmware against their will. I don't want to give money to a vendor I would just be antagonistic with.
If they announced they formally endorsed use of FreeSleep as an 'advanced alternative', ok, but that isn't going to happen.