I've run both pretty extensively.
I prefer 2e D6. The entire catalog of D6 Star Wars defines Star Wars. Even beyond the cinematic material, beyond the video-games, it fully encompasses all other mediums and has influenced those other mediums on fundamental levels.
System isn't perfect, but it does everything very well.
However - FFG's game captures Star Wars very well. I own the all three lines in their entirety (except the new Ships book - which is fantastically hard to find, but it's just a collation of mostly of ships in all their other books). And it is very complete. The line could end right now and it would stand very well on its own.
What both systems "stumble" on is playing Force users alongside non-Force users without making those Force Users either too weak, or ridiculously too powerful, based purely on the XP curve. If you ran a Force user campaign - you're in good shape. In FFG Star Wars a basic Force User, like in D6, will always be struggling to split XP between their Force powers and Skills. In FFG you can mitigate this with a Talent Tree purchases , but it amounts to the same thing.
If you want those Force Users to be dedicated Jedi/Sith - you're in for a LOooooOOOOng Grind. If you want to play semi-experienced Force Users most GM's grant an additional 150 points for "Knight Level" play... and honestly? It barely scratches the surface. It's not that the FFG system doesn't handle the Force well - it does so very well (arguably better than D6 in terms of "flavor" - but this comes from having a decade+ of latter era development). It's tricky to do a Jedi/Sith + non-Force user game.
If you want to play a non-Force User game... both games are excellent. I think D6 is slightly better overall. But FFG's game is close. The production value is *excellent* the art is good. And contrary to what a lot of people believe - it does not require meta-mechanics nearly as much as naysayers claim. There is tremendous support for it as well (And D6 has *never* suffered from lack of support either).
The only downside to FFG's game that I find commonplace, but did not impact me at all (and I thought it would) - is the dice. It turned out to work very well for me and my group of grizzled asshole players. If I say Star Wars is on the table - and they're ALL D6 veterans, they will choose FFG first every single time. I've tried to get them to go back to D6 - they won't have it.
So my thoughts? D6 is probably slightly better. My reality? I run FFG with D6 material as fluff supplementary material because it's rock solid and my group loves it more.