I don't recommend going via Qatar if you are in cattle class. Until they open their new terminal, there really isn't much available in the economy terminal. We ended up paying to go in the lounge.
Yeah, I've never had more than a 90 minute wait between flights in Doha (Several different routes), they seem to do transits pretty well.
Agree that the current (Temporary) terminal has limited amenities (Which is usually mitigated by the short transits) but the new airport should be open soon! (Already used by cargo aircraft)
All that said, however, I still prefer Emirates over Qatar