Concerning the workload: As far as I'm concerned, the academic workload is definitely not all-consuming. From watching my colleagues, I came to the conclusion that everybody chooses their own workload. Some of my coworkers come at 9AM and leave at 4PM; others think they absolutely must finish that experiment and stay until 10PM. Some people think they must immediately rush to the lab if their supervisor sends them an email on Saturday afternoon; others just ignore the email until Monday morning.

I have never heard of anybody getting into trouble for turning their computer off on the weekend, or working normal hours; I think much of the pressure is self-inflicted.

Personally, I currently work in academia (doing my PhD), and I run a profitable business on the side (selling my own software). Sometimes this is a bit stressful (when you have to prepare a talk and keep getting emails from customers because of a nasty bug you introduced in the last release), but most of the time this works out just fine.