SE5 adds some great new gameplay features to the series, in theory. In practice, the UI and AI and bug-lessness haven't caught up, so I'm waiting for lots of patch improvements before I try to really get into it. Meanwhile, I'm hoping it's a nice preview of things that will work well in future.
My guess is I will start wanting to play SE5 in about a year, assuming patches fix the UI, AI and other problems that can't be modded at Malfador's usual industrious rate. It also seems like very little effort was made to balance the stock techs (they seem far less balanced than SE4 even), so I expect a balancing mod will also always be wanted for SE5, but thankfully that task is already in capable fan hands.
Meanwhile, Dominions 3 is a solid release, and personally I like it at least as much as I like Space Empires. But it's a different kind of game, so not all SE fans will like Dominions (e.g. Fyron
).
PvK