Shows alot of promise but is ultimately ruined by game mechanics.
The expansion as such introduces one new planet to the game without a space sector. The planet is mustafar, home of the final showdown between obi-wan and anakin at the end of return of the sith. The planet as such is very well developed and is more open than kashyyyk from the previous expansion return of the wookiees. However it still has some design flaws and invisible walls still plague the scenery.
The amount of content in this expansion is not overwhelming and it is my opinion that other games present this amount of content in one or two patches. Instances aren't that difficult, even the final showdown with HK-47 of KOTOR fame was completed on the first try. I emptied the expansion of content within one week which is alot less then I expected.
All in all it has a few of good quests with a nice plotline leading up to the "fate of the galaxy" quests where you have to help the spirit of obi-wan. The quests in galaxies always feel well designed at the cost of quantity this is true for this expansion aswell. If you plan to stay with SWG after the disasterous changes you will want to get this expansion. Otherwise this isn't enought to keep you playing SWG.