Agree with pretty much everything in this thread. First time I tried an FDL (unengineered) I hated it and couldn't get rid of it fast enough. Tried one again a few months later with some basic engineering and still couldn't see what all the fuss was about. It was fast, and the weapon options off the chart, but it didn't "do it" for me. So that one went too.
More recently I've tried for a third time, now I have the cash and resources to A-rate and properly engineer the beast, and I've come to the conclusion that it just isn't for me. Getting the best performance out of it is like flying the TARDIS; you are constantly having to juggle something just to keep it doing what you want. Kind of fun, but exhausting. But my biggest disappointment was that the TTK for my preferred general loadout -- a mixture of beams and MCs -- was no better than my partially engineered FAS. Being able to stick to the back end of an Anaconda loses its appeal for me when I have to apply an insane amount of brainpower and manual dexterity to stay there, and stay there for longer. I'm sure with practice and patience I could come up with a combination of weapons and engineering that would minimise this, but the general improvements for PVE that the FDL offers just don't make it worth the effort IMO.
I'm sure for PVP, properly outfitted and engineered to the current meta, the thing is an absolute beast. But for PVE it's probably overkill unless you really enjoy the challenge. I went back to my FAS, spent the last of my Engineer time bolstering its shields, armour and utilities (fast-scan KWS FTW) and never looked back.
Having said that, this was the first time I didn't actually sell the FDL. Stripped it and mothballed it, but I've kept the hull. So maybe there's something in there that speaks to future possibilities. But right now it's FAS all the way.
I would recommend the OP give the FAS a try. The rank grind isn't too onerous once you find a good cluster of Federal-aligned systems offering missions, and it's relatively cheap to buy and outfit. Certainly cheaper than a FDL, and more versatile than a Vulture. Mine is totally geared for bounty hunting and PVE combat these days, but if you're short on resources and can't specialise your ships the FAS makes a great mission runner and light cargo hauler too.