Couldn't resist adding one more point, and that would be (okay so two more
)--support and community. Shrapnel is very responsive, unlike some of the juggernauts that seem to auto-delete your E-mails upon receipt. And Shrapnel is awesome about supporting product that's been out for a while!
Also, visit any of the Shrapnel Games forums and you will see that people in the community are *very* helpful and nice. When you stop to consider that the community involvement is totally voluntary, it speaks very highly of both the company and it's customers.
Add that to this game, which is just phenomenal in and of itself, and you have a product that I'd gladly pay $50 + for. Heck, it's something you can play over and over as different races--not to mention I'm sure that there will be stuff added over time.
Anyway, just popping in to throw out more of my opinions.