The Nova is a fantastic stove, as others have said, it simmers very well indeed. When you first light the stove, you get a really good vertical burn, but the Optimus engineers have done their homework well, put a pan on the stove and the height between the pot supports and burner is perfect, leading to a very good flame spread which heats evenly. Burn times are better than the Primus Varifuel, a little better than the Omnifuel (but not worth worrying about, the Ommi is also a cracking stove).
The build quality on the Nova seems to be tougher than the Primus, I would guess they will take more of a hammering in the long run. Fuel consumption I have not measured yet (being a sad stovie guy I will at some point), but at a guess, because you can simmer so well, I would think the Nova to be good.
All stoves have good and bad points, one yardstick I use, is to see how big the maintenance kit is per stove model, the Optimus and Primus kits are small, the MSR are big, does this tell you something?