Even with the quirks I noted, my overall energy level when I got done driving was significantly better than a non-assisted drive. Just the fact that I didn't have to modulate a brake/gas pedal helped. Not to mention the lower attention level required to keep lanes centered in gusty conditions. I'm totally spoiled now.
This is something, IMO, that really needs to be experienced to really 'get.' I used to avoid driving my Viper on days when I knew there was a risk I'd be stuck out late because the amount of attention it required (compared to my other cars) was punishing when tired. Autopilot in my 3 (which I use extensively due to my ~30 mile highway commute) puts a similar gap between the 3 and any normal daily driver. It just takes away so much of the low level stuff that you don't even notice in a normal car because you never had the option of taking it away. Once you have experienced it though driving a normal car is obnoxious and raises questions like 'Why do I have to manage brake and gas in stop and go traffic'?