I bought it as well last night, and funnily enough, I was about to post similar things as BlankO
The interface is truly a work of art, and I fully agree with BlankO, it's one of the best and most inutuitive I've ever seen.
I like it a lot so far, and it's addictive as hell, but I am not sure it'll have much staying power. Of course I can't quite judge its depth already, but I could imagine it gets a bit repetitive - no campaign, maps all look pretty much the same, and most probably not as varied as Civilization or GalCiv.
The scale is awesome (reminds me a lot of TA/SC), but it lacks the grandesse of Homeworld - if this game had a Homeworld setting (and slightly enhanced HW II engine and artstyle), I'd love it a a lot more - as it is, it all looks a tad generic, and lacks atmosphere a bit.
Slight problem with the difficulty level: I've won my very first game, 1vs1, on "medium", without many problems.
Sounding a bit negative here, when in fact I played till 2 AM, got up at 7 and played for another hour, and can't wait to get home to continue playing...