Best part is the character customization. I look forward to bending over backwards spending years mastering every job to create the ultimate super character.
Worst part for me -- and I realize I'm skirting the NDA -- has been the controls. No, I don't want FFXI's control scheme. WTB a real mouselook and tighter camera controls.
I'm also worried about the info drought but right now with things progressing into beta, I'm guessing the hype machine is on full blast. I hope SE doesn't think the Final Fantasy brand name will be enough to bring in subscriptions. The MMO-sphere is a hotly contested territory and things will be very hectic this winter between Cataclysm, free LOTRO, and (likely) SW:TOR's closed beta.
Not in closed alpha, so anything I say here is pure speculation.
It's not that I minded FFXI's control scheme, but WASD and arrows are more of a standard control set, not just for MMORPGs but for FPS as well.
With FFXI, standard hand positioning for me were right hand alternating between numpad and mouse, left hand resting on the keyboard with the base of my little finger resting over ctrl and my thumb over the spacebar, to the left of alt.
I got used to it, but I would much prefer a system of WASD movement with mouselook. I have to admit I like the Ctrl/Alt 1-0 scheme that I got used to in FFXI; even in WoW I tended to keybind everything the same way. Primary bar was 1 to =. Lower right bar was Alt and 1 to =. Right bar was Alt and 1 to =. Right bar 2 was Ctrl+Shift and 1 to = and lower left was Shift and 1 to =. There were occasional exceptions (Ctrl+G for Ground mount, Ctrl F for flying mount, ctrl H for hearthstone, etc) and when I had memorized an entire bar, I just hid it. (Lower left bar stayed hidden a lot, so did right bar #2).
FFXIV looks to have a hotbar, I'm hoping that the alternate hotbars are customizable. I also noticed in some of the demos that it looked like they were using the arrow keys to select options on the hotbar instead of numbers; I'm REALLY hoping that you can use numbers or that could get annoying fast.