Very simple, bought one, love it. If the auto-away doesn''t work for you turn it off and manually away from your smart device or their website. It's already saved us money. Nest said the average RoI is 2 years. Not bad for something that will likely hang on the wall for 10+. It auto updates after attaching to your wifi network and going through setup. Some of the features in 2.0 are awesome it will turn off your AC compressor before turning off the fan to get the cooling left in the compressor cycling through your house to save you energy.
It has gone auto away on my wife and I a couple times when we haven't walked by it in a while. But it doesn't recognize the cats as people either so not so bad. Overall I like it a lot. And yes, the guy who started the nest team is also heralded as the father of the iPod, so there's where the spinny clicky interface comes from.