The FAS is amazing. I run a large beam on the top and 3 PAs on the bottom (everything fixed of course) and it's a ton of fun. Engineering has only made it better.
People say it's like a vulture on steroids but they are missing one important point: the vulture is more of a shield tank whereas the FAS is a hull tank. I run a hybrid build with biweaves but between 1800 hull hp and MRPs losing your shields is just an annoyance. It takes an adjustment to get used to.
I recently sold my FDL in favor of my FAS. (FDL was going to be the upgrade from my FAS) but...just couldn't like the FDL. Then first fight in the FAS 5 v 1 (PvE) my shields dropped and I had that brief moment of "Oh crap" before I remembered I was in my FAS...and laughed as they barely scratched my hull while I took them out.
Ended the fight with 78% of my hull left, almost the entire fight shield-less. It made me happy.