Two years ago I faced the same questions you did. My final call was the DVR-XP.
First, I would not try a large vessel, on the Nova, off-axis. The tool support, etc is simply not up to the task (and I have the out-board tool rest).
Second, if you are really worried that Teknatool will stop marketing the motor (they don't make it, someone else does), there will be 3rd party support, but it will (probably) not be cheap.
Third, if space is an issue, the DVR-XP is the clear winner
Fourth, the DVR-XP produces more power on 220, without swapping out the motor (Teknatool says 2HP, no it's not a myth or mere marketing)
Fifth, if you need a different height, then the factory height, the DVR-XP lends it self to a custom lathe stand more.
For me, and my needs, the Nova came out ahead, and I think it still would.
Making sawdust mostly, sometimes I get something else, but that is more by accident then design.