I hate STEAM. I'm hostile to anything even remotely similar to STEAM.
Stardock won me over with Impulse, though. It's easy to use, streamlined, has a few nice features, and for the love of all that is holy - you can actually turn the damned thing OFF. It doesn't need to run to do anything more than update your games, once that's done you can turn it off and be free of it.
In addition, Stardock seems to be an excellent company - and they consistently provide great customer service. I've yet to have any problems with Impulse, and it is infact the only digital distribution software I trust enough to regularly use (or for that matter, use at all). Since SOASE, I've purchased several times from Impulse, the latest of which was Evochron Legends (awesome little game) just a couple of weeks ago... and again, I have thus far not had even a single bad experience with Impulse or Stardock.
Also, while you're right - it doesn't mention obtaining updates via Impulse on the box (I have thoroughly checked my box), it does clearly state in the manual that comes with the game on page 8 that you will need to register your game's unique serial number with Impulse in order to obtain updates of the game, and that it also gives you the right to download the full version of the game at any time in the future for no additional charge - which is quite handy if you break your disc somehow.
In short, relax - you're in good hands! 10 minutes or less of account setup and downloading Impulse from www.impulsedriven.com and you're golden.
Welcome to Sins of a Solar Empire!
PS: Vasari own all.