I've been playing a prototype of Eminent Domain. Seth Jaffee provided the files needed to print it out, and I've been playing 2- and 3-player games over lunch. It took about a half dozen plays to get all of the rules right, but we even enjoyed the game when we were playing it wrong.
Briefly, it's an engine-building game that utilizes role selection and deck construction. In fact, the role selection is the method for adding cards to your deck, which forces you to weigh the desire to use the benefits of a particular role with the consequence of adding that role card to your deck. There are three ways to score points (planets, technologies, and trading), and so far it has proven viable to pursue any combination of these three. That's the short of it; I'll let the BGG entry and Seth's blog add details.
Our last two 3-player games proved to be extremely close. Starting with a fertile planet, I pursued a harvest/trade strategy, trying to take advantage of reasearch, survey and colonize when possible. My opponents dabbled enough in harvest/trade to take some advantage of my calls, while also using warfare, colonize, and survey to play some high-point planets. The VP token pool exhausted to end the game, and the final scores tallied 21(1)-21(0)-20 (I was the 20). The winner had successfully been collecting armies with a "Take 2 armies" technology action, and then utilized a single warfare card to occassionally attack planets. Otherwise, he primarily relied on colonize to settle planets, while also gaining moderate VP tokens. A single leftover army won the game for him.
In our second game, I drew a fertile world to start again, but decided fairly early to eschew the harvest/trade strategy for something different. Instead, I tried to use a combination of warfare and colonize, along with some research and survey. Unfortunately, my surveys were fairly shallow, and I was drawing fairly low-point planets. I was last, which is a nice advantage in that you can guarantee yourself a win if you know that you can end your turn with more points than everyone else. (Points are fairly easy to track; the only "hidden" points are on research cards purchased and placed in the player's deck, but these are not so many that they are hard to remember.) When it came to my turn, I recognized that I could end the game while also building a 5-point technology, and it was unlikely anyone else would be able to research for points. However, this would have tied me with the leader, who also had some armies while I had nothing to help in a tie-breaker. Instead, I extended the game another round. I believe I researched that round for 2 points, and then followed a trade or attack/colonize so that by the time it was my turn again, I was only down by one point. The leader exhausted a role card pile on his turn, which was immediately before mine. Down 29-28, I held only 3 research symbols in my hand, but I also held a tech with a "Draw 3" action. I played that tech, and drew 3 cards. Only 1 research card came up. With no other way to gain points, I was forced to end the game 1 research card short of victory. Final score was 29-28-27.
Eminent Domain is well-received with my lunch group. Although it fills a different strategy space than Race for the Galaxy, there is one major similarity that forces it to compete for playtime: we can play two games of either within 90 minutes (yeah, we take long lunches if we're playing games). The role-selection also gives a similar feel where it's important to read your opponent, and gauge the optimal play based not only on how it helps you, but also on how it helps your opponent. The deck-building mechanic in Eminent Domain adds another layer to the role-selection, which complicates that decision. However, the cards are much less complex, which makes it easier to teach and learn Eminent Domain. If I had a group that wanted to learn both, I'd probably teach Eminent Domain first.