Right on! I think I narrowed the issue down to the betas. When I try to 'option+update' it'll brick my phone and gimme the 'SIM not valid', but regular updates (at least in iTunes anyways) will work. Had my 4th iPhone updated at the Apple Store after they replaced my 3rd.
I'm on my 5th iPhone 5s now and it shipped with 7.0.4. I updated to 7.0.6 via iTunes on Saturday and it worked great. I'm still nervous to install 7.1 😱 lol