Only two? .. :-P
Seriously... I see not much point on discuss product that has not been shown IRL and has no been evaluated by independent people. I know that some people (expecially their markettroid Ben Hermans) have a great belifs that it'll be something revolutionary, but quite frankly.. Not much of a realism there.
There are hundrets different OS (+ thousand homemade variations) there, and quite frankly I would be hardly supriced IF they had actually innovated something new and different during their first tumbling at the OS making.
Well.. recorded miracles have happened before. But I'd rather look this OS4 first before entering into too much discussion if it's worth havin or not.