I won't defend the price they have Dom3 at, I don't think it's possible. Shrapnel is a shit site and a shit publisher in my opinion as well. But none of that has anything to do with the quality of Dom3. Granted, it's really not everyones cup of tea, then again what is?
I think the point which needs to be stressed for Dom3 is the massive amount of content. Nothing, and I mean NOTHING, even comes remotely close. Some games (paradox bullshit) confuses you with overly complicated mechanics for content. Not that those games are bad per se, just that in this regard they fail massively compared to Dom3. Then again, the amount of content can also work against Dom3, for those who don't want to deal with it. As does the late game micro hell. As does the shittastic AI. As does the outdated (HA! understatement) graphics.
Well the AI is only there so you can test stuff in SP mode, it's not really meant to be challenging, and unless you handicap yourself, or play various mods it's not remotely challenging.
Anyway, Dom3 is one of those games which tests that maxim, that it's not what it looks like, it how it plays. Granted, everyone has a different threshold for that, but if multiplayer complex TBS in a fantasy setting floats your boat, the it's really hard to beat Dom3. Unless you expect some RPG nonsense in your TBS games. Well even that is kinda in Dom3, just not really done in a particularly meaningful way, since it's not the point. Though once you get to the point where you can forge all kinds of good equipment and summon up your SC badasses... well they are one man armies, laying waste to 100s of units. Kind like what we thought Elemental was supposed to do... heh.
So in short, be careful with this game. If $55 is a lot of money for you to spend on a game (and it is for me) you better be damn sure you know what you are getting. The demo doesn't really give you the full flavor either, because it's limited to just a few (couple?) nations. Don't recall if it also limits turns or research, but it does give you a feel for the basic mechanics. Just that the basic mechanics are the tip of the iceberg. Because past those, once you grok them, you can play with all the various combinations available to find the path you want to take to bend those mechanics to your will.