Let me start by saying I do believe this is worth buying but I caution you if you are a fan of RTS games that this may not be what you are used to. The modding community has also done wonders with this game and for the Republic at War mod alone is worth buying the game.
The game is split into 2 distinct parts. The galaxy overview where you build bases, move your troops and play in a Risk like format. The second part is the the RTS side of the game where you control your troops directly. This is further split into space combat and ground combat. I'm going to give each a review and then add the sum for my total review.
First with the ground combat it always involves protecting or destroying the buildings. The defending side get's units through deployed troops already built and gets further free troops from buildings designed to construct units. The offensive side I find often is at a disadvantage and it becomes of game of invading with totally overwhelming numbers or playing more tactically with stealth based units. This generally ends up being long winded and downright boring battles in the later parts of the game where the combat is meant to be more fast and furious to keep a game going. For the ground combat I'd give it a 2/5.
Second the space combat. This is where the game really shines and you can recreate some of the great moments from the movies. The Rebels and the Empire both play very differently and it keeps the fights fresh each time. The Imperials go for that ovewhelming numbers and get free Tie Fighters and bombers from the capitol ships. The Rebels why they need to buy Fighters and Bombers are generally more well rounded to deal with threats. Capitol ships on both sides play fairly the same with your standard Rebel Crusiers and Star Destroyers but what makes space combat so unique is that larger ships and space stations have hardpoints to target. To many Tie fighters take out the hangar. Mon Calamari Cruiser flanking around you take out its engines and leave it stranded. This adds a whole new dimension to and RTS that I've never played before and makes it a truly tactical experience. Space combat gets a 5/5.
Finally the Galaxy Overview portion. It's fairly straightforward and just involves moving units, building bases on planets, sabatoging enemy bases and upgrading the tech tree. For players who don't want to play the battles can actually play and entire match from this screen and let the computer simulate the battles for you. It's different, it's cool, it's noting totally special but does offer a new take at strategy games. The Galaxy overview gets a 4/5.
Don't expect much difficulty from the computer. The AI is somewhat dissapointing but fear not. One of the best parts of this game is what the modders have created for it. The Republic at War mod can take the place of the expansion and allows you to play out the Republic vs. Seperatist conflict. The AI in that is tough. I'm at the point where all I play is Republic at War and it offers the challenge that I was looking for from an AI in an RTS. AI gets a 4/5.
So when you add it up the game is a 15/20. That takes into accounts both the vanilla game and the modded game. The modded version is much better and totally free so it's absolutely worth getting. Vanilla version is more for people who want to learn the game or are big Star Wars fans. In all it's not super difficult and definately different from most RTS games on the market. I definately recommend this game!