I'm in a similiar boat as you, i've been playing RPGs for nigh on 30 years, including all editions of D&D (1-4e) and SW (d6 & d20), and I honestly do recommend SW Saga. I've dm'd it for the past 8 months and I really have enjoyed my time with it and I'm about to start a new story arc, but I've also been on the otherside of the screen as a player.
For books, I'd recommend these at the least.
1. Core book.
2. Threats of the Galaxy
3. Starships of the Galaxy
The rest are optional and with utility & quality varrying. I rate Clone Wars & Scum and Villainy as well worth getting, but Legacy Era sucked balls in my opinion. The KoTOR & Force Unleashed books were... meh.
As far as "what's allowed", I would highly recommend doing a flat "if it's in the corebook, its okay. Everything else requires prior DM approval" rule because some of the force powers are very dubious. For instance, in Clone Wars there is one for turning invisible and another for phasing through walls. For my group, I established a tacit understanding that for the force, we'd stick as close to the "feel" given in the movies as possible and it has worked out well.
The combat is frankly where the system totally sells itself to me. The Condition Track is just a great mechanic that allows you to get around the whole suspension of disbelief where people stand in the middle of combat just soaking up blaster bolts. i.e. hp = ducking/dodging/getting tired. condition = you're getting progressively hurt. Add on the things like parry/block with lightsabers is _MUCH_ better done as well.
The force powers can be _WAY_ over the top if you have a well built character or someone who min/maxes the hell out of it. I'd recommend an optional rule of the Force Training feat as something you can take only once at the start and then at the 3rd/6th/etc... levels until Jedi Knight. I know that seems arbitrary, but a Jedi with a high wisdom, skill focus use force, and force training x2 at level 3 will flat out dominate in fights. They are crazy over powered. Particularly since several skills both incapacitate AND damage (Force grip/Force Whirlwind) AND are sustainable from round to round. So a Jedi can, without a huge amount of difficulty, lock down a single bad guy for an entire fight. While not an issue with minions, if you are the "big bad guy" sort of DM, it could be annoying. Plus as mentioned previously, Move Object is sick if used by an intelligent player.
But all in all, I absolutely love the system. It's both simple and eligant. It's a very nice improvement over 3.xE and what 4e shoulda been if they'd have been smart. Instead they over sampled and turned 4e into WoW on a table top. So I really do highly recommend it.
One word of caution, and may be this is just me, but the combats require more thought and planning if you are going to really have fun with it. It's no longer just a charge in and hack orc. Now the bad guys need to use cover and maneuver and combats happen in 3 dimensions in it. In my last game, the PC's walked into an ambush with a sniper on a 5 story roof with tons of cover and ground support. It was messy until they wised up and started thinking in 3 dimensions too.
In the next one, we are going to explore the magical world of orbital fire support!
The space battles are SO MUCH better done than d20 SW. It too is simple and easy to do and the multiple roles on a ship gives everyone something to do. Plus it's not that lame ass totally abstract thing. It's not uber complex, but it doesn't need to be frankly.
Finally, and this is a PURELY subjective thing. At first when I was starting out, I approached it from the perspective of "this is a star wars game" and so I kept wanting to incorporate canon stuff. Then it finally clicked that "no, this is a sci-fi game" and things got a LOT more enjoyable for me.
Whoops, almost forgot this: It's the thread where about the best of the
character generator spreadsheets is done. Threats to the Galaxy does a GREAT job, but the later editions of Ben's (1.29d) is really good and helpful for whipping out NPCs that are more combat optimized. It also really helps for players and their first character.