It's alright. But I wouldn't want to spend 11 hours there!
I suspect that the OP won't be eligible for free transit accommodation since I believe that there should be a shorter connection available than the one booked (but without knowing the dates it's tricky to confirm that).
Ok, compared to BA's T5 Galleries Club lounges, Al Mourjan is alright
I do agree, however, that 11 hours in any lounge is mindbogglingly boring. Maybe the OP can get out of the airport at into Doha itself.