If you mean in terms of sound you really need to listen for yourself, with your own source/speakers and ideally at home if dealers are obliging enough. I'd be surprised if anyone here as heard both, though I may be wrong.
As above. The number of valves used is different but weight is very similar.
Obviously design layout and overall looks are different as is the actual output wpc.
There is quite a price disparity between the two, at least in the UK, and to get similarities you would be better comparing it to the Evo 400.
The Primalunas are more user friendly with auto biasing of valves and the possibility to switch to Ultra Linear mode. It also makes tube swapping easier.