I've had nothing but great experiences with 4.3. It fixed the slowdowns I was having with my old Nexus 7 and improved browsing performance noticeably on my Galaxy Nexus and Nexus 7 (probably from the 2D rendering improvements). I also have a new Nexus 7 which might be the first Android device...
I'm not worried about the battery life aspect, but I absolutely hate it when devices decide that they're smarter than their users. This whole driving sensors thing screams of this.
Take in-car navigation systems for example. The designers decided "hey the driver probably shouldn't be typing...
It depends on which L-shaped connector you broke off.
There should be 2 connectors on the drive. One short one which is for data and one longer one which is for power. You can use the Molex connector as a substitute for the long one, if that's the one that broke. If you broke off the short one...
My first thought is that your PSU may be the problem. If a period of high load causes your PSU's output voltage on 3.3/5V to sag enough to reset the spinning hard drives, they may not get recognized again by the OS if it's not expecting them to be hotplugged. It's a bit of a shot in the dark...
Shield interests me as a CPU enthusiast. I really want to get my hands on some A15-based hardware to play with. Right now the only A15 stuff we have in North America is the dual-core A15 SoCs inside the Nexus 10 and Samsung Chromebook. I'd like to play with Android on a quad-core A15 SoC like T4...