This thread went 3 years with no replies, but I figure since it got 25k views I'll answer my own question.
GFF (Grond's Final Fantasy) -
https://www.romhacking.net/hacks/652/This is a very awesome hack, but not my favorite choice. Still, GFF might be for you. It fixes bugs and has a lot of quality of life improvements. Too many to list, so just check the link if you want to know. There's a few things that I really like about it. It animates some tiles like water which gives the game a lot more lively feel to it. It gives you a save command in the start menu, so you can save you game at any point on the overworld map just like in other FF games. Names of most things are expanded. You can dash by holding B. The in-game map looks better and loads faster.
Final Fantasy Restored -
https://www.romhacking.net/hacks/1631/FF Restored is another highly praised hack, and the one I went with (along with some additions). Like GFF, it fixes the known bugs in the game. And it has quality of life stuff like holding B to dash, auto sorting usable items at top, etc. What I really like is the added "buy 10" option for item shops. Again, too many things to list.
Final Fantasy Hasted -
https://www.romhacking.net/hacks/7482/FF Hasted really works best when combined with FF Restored, and that's the combo I ended up playing. Hasted does a lot of things. Again, too many things to list. But probably my favorite is character poses in shops. Using character's normal, celebrating and stunned pose when selecting armor or weapons dictates if they can equip it and if it's better than what they currently have equipped. It also adds a tweak (that you can revert back) that characters don't attack an empty space after an enemy is defeated. And as the name implies, it speeds up many things like transitions, victory celebrations, etc.
I went with Restored + Hasted mainly because of the shop poses, buy 10 option, and not attacking empty spaces. Otherwise, GFF would have been more of a contender for me.
One thing that did kind of bother me about Restored is that it cut off the peninsula of power. I mean, I rolled the credits and still very much enjoyed the game, but I thought it was stupid to axe it. Luckily, there's a patch for that!
https://www.romhacking.net/hacks/4675/It also reverts all of the items names in shops, which I have to admit, I like the new names.
Both Restored and Hasted have optional patches to customize the game to your personal preferences. I went with a patch that took out the ship mini game to make room for new music. So bosses and sub bosses now have their own music, which is awesome. There's an anti grind patch for Hasted, which I experimented with, but I found it made the game too easy and completely over-leveled you.
So long story short, if you're looking to play Final Fantasy for the NES with bug fixes and quality of life improvements, then go with either Grond's Final Fantasy or Final Fantasy Restored. If going with Restored, there are numerous optional patches including FF Hasted as well as other addendum patches.