I've been watching a lot of gameplay videos of this lately and it looks great. Also, Paradox (the Stellaris team anyway) seems like a really cool company, I had fun watching them play... I think I'm a fanboy of them now too, haha.
One thing that I really like is how it seems to have elements of Civ in it. Reviews have confirmed this by saying that it's a hybrid of Paradox grand strategy 4X and 4X of other games, like Civ. So, it's more accessible and easier to jump into than their past, historical grand strategy games. I usually prefer tighter, more streamlined design without sacrificing depth. I purchased EU4 in the past; maybe I never gave it enough of a chance but I quickly stopped playing it because I didn't want take the time to learn it all (and I like random maps -- playing the same, realistic Earth map seemed dull to me).
Stellaris looks like another solid title I can add to my very selective collection that I play regularly. Plus, it'll probably get loads of DLC to expand upon it like other Paradox titles. Without the design-shackles of history, I'm excited to see all the things that they come up with!