SP3 is a great piece of hardware but unfortunately it has it's own problems.
I have mine since release and I hardly heard the fans.
There are some issues with the software but I did not notice any of yours. I had a problem after updating the OS....long story short...I had to restore to a 6 days old restore point to get it to work again (it was just stuck on login screen). I was frustrated as I did not now how to restore. It turns out you had to press shift key and select restart in recovery. The option will not show, unless you press the shift key.
As with your problems, I would check if there is no app that is causing the problems you have.....It might sound sily, but I can not think of something else.