'test the waters' of Impulse !!!! The only real alternative of Impulse is Steam... the only real way to "test the waters" is give to both the same right of distribution and see who is the best...
There's also GamersGate, Direct2Drive and their own online store as well, but I think it's more of a "vs effort" comparison, see if they get enough sales to make it worth their time dealing with Stardock at all, but that's just my personal speculation.
I wont lie, this turned me a little off. I was looking forward to it. i may still get it, but being one of those damnedable "fps flashy lights" people, we will see.
Then I'd recommend playing Mass Effect first, Bioware's previous RPG (and whose sequel is coming next January, already confirmed to be on Impulse). The combat system is pretty much that of a tactical FPS, like the Brothers in Arms or Rainbow Six series, except you can also use some special powers (think Star Wars' Force) in between, so its much better suited for action FPS players than that of Dragon Age. The only problem is that its still not here on Impulse, but it's been confirmed it'll be available before ME2's release and, if you still can't wait, it's only $20 on Steam.