Much to the chagrin of my wife I have played this game almost every waking hour not at work since purchasing it. To understand the quality of the game one has to rate it based primarily on what it attempts to accomplish. So one must base the success of quality of Sins on how it handles the 4X idea as an RTS.
eXplore - You start out with direct visuals on only the planets you and your allies own. The only planets you even know exist are the ones with phase lines connected to your own. From then and there you must seek out the location of the planets (where the types change even playing the same prebuilt map). You can even explore your own planet to discover trade goods, artifacts, and other useful items. Hovering over a planet will inform you of the ships and structures last seen there with a timer to tell you how long ago it was. There are plenty of unique planets to discover early on and recon is an extremely important aspect of the game even from the start.
eXpand - Considering the possibilities for a 6+ star map with 100+ planets, you can rest assured there is plenty of space in the galaxy. Your empire can grow to quite the evil grin faced amount. The colonization system for actually taking over a planet is simple and intelligent.
Where this game lacks here is the strength of culture. Overpowering amounts of culture/influence that you can develop in a game like Civ4 or GalCiv2 are not to be found here. As it stands culture is only useful as a defense in preventing far invaders from colonizing your planets. And everyone knows offensive culture is where the fun is. The problem is two fold. One, it's very hard to generate a significant amount of culture to overthrow a planet without the Advent's Deliverance Engine. Two, when you do overthrow the opponent simply loses control of the planet. You don't gain control of the planet nor any structures that the player owns. As it stands the trade off of military troops for culture is very poor.
eXploit - Between trading, planetary upgrades, three resources to balance, artifacts, and a huge tech tree there are plenty of ways to improve the infrastructure of your empire. The balance between what to build is well done as there are no wrong choices (other than building too many culture structures). Just make sure it fits into an overall strategy!
eXterminate- My favorite X! Simply put, the battles in this game are amazing. Instead of offering the player much better units as the game continues, Sins offers you DIFFERENT units. It's up to you in how you make up your fleet to find that right balance of ability usage, armor, and firepower that will overwhelm your opponent. Siege frigates live too long as of this version but that will be changed in the next patch.
Unfortunately another flaw is found in the diplomacy system. Everything is just too limited. The mission system is a good idea but why do the missions feel like they don't make sense? Why does the AI want me to attack a player that's not near him nor one that he's fighting. Why not add defensive missions that require a certain number of units to sit on a planet for a given length of time? Why can't I assign similar missions to the computer? There could easily be a "favor" stat that informs the player how much another empire is willing to do. Money doesn't seem to do anything to affect how someone feels. 20k credits later and 0 increase in relationship. And why can't I ask for money? Why can't I just ask a player who I only have a cease fire with to attack someone else...I'd be willing to bribe him if I could! The mission system is a great way to transition diplomacy from a TBS game to the RTS world. But...it must expand functionality, reciprocate actions available between player and AI, and show more logic in the AI's requests.
Thank you for taking the time to read (all or part) of this lengthy post. This is a fantastic base game but what will make it truly amazing is the after release support.