This is all IMHO:
Saga is better than the other iterations of Star Wars d20 by many parsecs, but it still has serious problems. On the downside, like 3.x in general, it has serious issues with balance and power gaming (Power Attack, I'm looking at you). Not to mention, any game where a Wookie is the best choice for making a lightsaber duelist has some problems. The d20 system in general is just not a very good fit for the SWU. On the plus side, Saga has a
lot of material, and is pretty up-to-date as far as the Expanded Universe goes, since it only went out of print a couple of years ago. On the other other hand, that material is scattered through a ton of books without indices, often located in random sections (a piece of equipment might be in the Equipment chapter - or listed with a species that uses it - or a class - or an organization - or a planet where it's made - etc.). If you don't already have all the books, they can be hard to get, as they are out-of-print, and some of them are hard to find, and sell at fancy prices. You can find pirated pdfs of them, though, if you want to go that route.
I just finished running a SW campaign using my own homebrew rules based on Savage Worlds Deluxe, and it was quite successful. Overall, the system is a pretty good fit for the tone and feel of Star Wars. You can find a number of other homebrew conversions at
http://www.savageheroes.com. The big downside is all of the conversion work you'd have to do - there's just not much material in even the most complete conversion I've seen. On the other hand, SWD is designed to make conversions quick and easy, and it has enough similarity to d20 that you could probably convert quite a bit of Saga material without too much work. I actually enjoy doing that kind of thing, but if you're looking for a "campaign-in-a-box", it's not a good choice.
I actually still have a lot of fondness for the old West End Games Star Wars RPG, but that is LONG out of print, hard to find, and now badly out of date (I think the newest material is now nearly 20 years old). While the 1st Edition had some problems, it is still for my money perhaps the best licensed RPG product ever. The game mechanics and style of presentation just meshed almost perfectly with the feel and tone of the game world. And the "ads" (for INCOM's new T-65, Imperial Navy recruiting posters, and more) were, for me, much more evocative and immersive than the White Wolf-style bad short fiction and vocab lists that became so popular in RPG design a few years later.
If you're willing to do a homebrew conversion, I'd also recommend taking a look at the Cortex system from Margaret Weis Productions. It always struck me as being a good fit for the SWU. If you can find the now-sadly-out-of-print Serenity RPG books (which use a modified version of the Cortex core system), they have a lot of material that you could use for a SW campaign (particularly if your players are interested in playing fringers and scoundrels, dodging Imperial entanglements while scraping by on the Outer Rim, with a crew of outcasts and misfits and perhaps a fugitive being hunted because of her otherworldly powers...).