It's probably fair to say that the single-player aspect of this game isn't as solid story-wise as its predecessors -- and I do recommend checking out the early incarnations of the Jedi Knight series -- but the reason for playing this game is in the action and friends.
YOU GET LIGHTSABERS. You are able to choose between Single, Dual or Staff, which is a first for the series. YOU GET FORCE POWERS, being able to pick and choose which ever powers are offered from both polarities of the Force. AND GUNS. Well, maybe not as exciting as the first two, but the some of the guns offered here are the sort of things that only the SW Universe offers and you'll be hard pressed to find similar items in other games.
But what really takes the cake on this game is if you are able to play online with a great group of friends. You will spend countless hours with them. There is a community that has stood by this game throughout the decade it has been around and I suspect they will be around for even longer. Much of the community functions in an RPG aspect where people will form their own groups and incorporate SW lore into their gatherings while other aspects of the community will focus on the skill of brandishing the lightsaber. Even further, there are countless mods offered to further enhance gameplay and your experience.
So yes! Buy and play this game. If you want to play this game however, you should do yourself the favor and play the previous games of the series so you are familiar with the lore and whatnot. It will make the experience much more rewarding once you arrive at this title.
Aside from the hours Steam shows here, I've must of put in another thousand hours or so that are not shown. I've played this game over a period of 8 years and finally felt that I had enough. But I left with many memories of the good times I had playing. This is the game of my teenage years.