There are a few trip reports on people's experiences flying Qatar Airways business and with more pictures than the website.

SPA's arent free, but all alcohol, food and showers are free. Personally 3 hour transit time is ideal as you get about 2 hours in the Premium Terminal which is more than enough imo. With a 6 hour transit time you are looking at roughly spending close to 5 hours in the terminal. Which is a long time. Forgot to mention there is also a sandwich bar as well which is quite nice.

6 hours is not enough time to really get out the airport and see things nor do I think they will allow you to see things either.

But yeah get drunk, eat alot and get the most out of the experience of flying QR business. Depending on the time of the day the place gets packed and can cheapen the whole experience.

Personally QR in the air is where you get your money's worth.