And now a bit more on the subject at hand.
I realize I posted on this earlier, but I've been thinking about it a bit more, and realized I have a few more points worth adding.
First, a disclaimer. I've never been a star wars fan. When I first started playing the game, I had never even seen the movies. In fact, I watched the movies because I was a fan of the RPG, which is weird, I know. After I watched the movies, I was around thirteen or so, and for awhile thought that the Endor speeder-bike scene was AMAZING (I realize now it was because of the environment, but bear with me).
When we played d6 Star Wars, it was very much space opera as covered in the original books, but often with the serial numbers of Star Wars shaved off. It was also, by some unspoken agreement, "Jedi Lite". When we did play with Jedi characters, they were inevitably the "Quixotic Jedi" archetypes for some reason - hard-drinking former jedi who had fallen on hard times.
Anyways, we loved the game. We even loved some of those old ideas the game supported that no are no longer "cool" at modern tables - using scripts to set the opening scene, using a caller, and the like.
The strength of the game is that it supports many different types of gameplay using the exact same rules interface. Flying a spaceship is the same as driving a speeder-bike, which isn't much different than firing a gun or climbing a cliff.
But where the game REALLY flies is the action economy. Whereas d20 variants have a limited number of actions per round (in fact, most games follow this model), d6 allows many more actions - however, each action reduces all actions within that round. So, a character that fires a gun once might roll five dice for that shot. if he fires twice, he'd roll four dice for each shot.
Simple enough, but what this tends to encourage in play is PCs taking ownership of the scene, and actually describing their actions. In essence, a character will fire a shot, jump through a doorway, and then fire two shots at the guys on that railing above, all in one three-second round. Which is a very Star Wars thing to do.
I don't know what it is. But I've played games with hardcore d20ers who, when playing a d20 system, will say "I attack" or "I cast spell X". And then, two minutes into d6, are vividly explaining just how they fire their blaster while dodging incoming fire. Again, this may just be my table, but I've found d6 fires the imagination in a way d20 can sometimes have difficulty with.
Another poster mentioned that d6 only has coverage for a very specific era in the game, and that is probably true. However, d6 is VERY capable for on-the-fly rulings. Every time I've run it, I've been able to handily make NPCs with almost no prep - sometimes I can do it in less than five seconds. Only Savage Worlds comes close to this speed of play. Provided you already know the material, creating new mechanics is a breeze.
I have played d20 Star Wars (not SAGA, though). I was not impressed, for a couple of reasons.
First, the rules didn't streamline as well as d6. Flying a ship felt different than flying a speeder bike. And combat was something entirely different than a negotiation. While this might be a minor quibble, I've always preferred to mix up my scenes in Sci-Fi - so that while one guy is flying the ship, another is using the guns while a third is trying to plan a route using a computer.
Second, the action economy of d20 doesn't work to emulate that cinematic flavour. In d6, I can fly a speeder bike at top speed while also shooting a pistol at someone - this is more or less impossible in RAW d20.
Third, the characters in d20 are way too limited, in comparison to the source material. When you have X number of classes to choose from, and you have a character type in mind, sometimes it becomes a matter of sacrifices to your character concept because of the class you play.
Fourth, tracking wounds and vitality in d20 is fun and all, but I much prefer d6's "you're hurt or you're fine" resolution system.
So, yeah. I pick d6 as my system of choice for Star Wars. I feel it's the best cinematic offering out there, and one that really gets the players moving. In fact, it is still one of my all-time favourite systems, and it saddens me that the newer WEG stuff is often just a bug-ridden mess. I'd still play it today, and many of my players would be more than willing to switch as well.