I played it a number of months ago, but became very frustrated with the pirates...
When playing against adversaries, you must bribe the pirates every 25 turns or so to attack your adversaries. Although this is an interesting aspect of the game, there is no way to turn off this feature. And this is the ONLY strategy I found that works.
This became discouraging as it seemed I had to allocate most of my resources to bribe the pirates. If I ignored this aspect of the game, the pirates would attack me and always show up in the weakest system with a fleet that seemed to always be equal or greater to my entire fleet. The problem with the pirates is they are your only real weapon. If you ignore them, they and your adversaries will defeat you. If you use them, it requires too much of your resources to make a tactical attack on your adversaries.
I did try playing a game with just the pirates, which was a little lame. I found their system, which was... OMG... very tough to defeat and even after that the pirates came out of nowhere with a hoard that was a formidable challenge for my fleet. At this point I lost interest in the game.
It did get good reviews and I does try to give a RTS feel to a turn-based-strategy game. Although I think I liked Ascendecy a whole lot more which did the 4X thing before it was in vouge.
-kevin