FF I: 2/5
FF II: 3/5
FF VI: 4/5
FF VII: 5/5
FF VIII: 4/5
FF IX: 3/5
FF X: 5/5
FF X-2: 3/5
FF XII: 4/5
FF XIII: 4/5

Final Fantasy V :: 3/5
Final Fantasy VI: 4/5
Final Fantasy VII :: 5/5
Final Fantasy VIII :: 3.75/5
Final Fantasy IX :: 4/5
Final Fantasy X :: 2/5
Final Fantasy XII :: 3.75/5

FFI 3/5 - Too grindy.
FFII 2/5 - Broken and unenjoyable battle system killed it for me.
FFIII 4/5 - Very underappreciated for its time.
FFIV 3.5/5 - Boring and generic battle system with nothing special in it, but then again I only played this one later so it's hard to appreciate it.
FFV 3.5/5 - Battle system had a good idea, but it became too grindy. Also the story was a bit too generic.
FFVI 4.5/5 - Great game, but I could feel its age.
FFVII 5/5 - Best in the series. No complaints.
FFVIII 5/5 - Story was 2nd best in the series. Battle system could've been a bit less annoying, but overall it was fine once you got a hang of it.
FFIX 4.5/5 - Same as FFIV. Generic battle system where everyone was a fixed class and got specific skills. I don't like this kind of thing. Great world and story made up for it though.
FFX 5/5 - Best story in the series. Decent battle system with briliant progression system (Sphere Grid). Only complaint was straight linearity.
FFX-2 4/5 - Just watching those girls shapeshift made this game great for me. Battle system was awesome too. Story could've been done better.
FFXII 5/5 - The story in this one was good, but there wasn't much of it. What made it great for me is the amount of content and exploration. It had the best world design in the series. Just fighting and exploring was enough for me to really enjoy it. Best battle system in the series.

FF I: 2-5
FF II: 3-5
FF VI: 4-5
FF VII: 5-5
FF VIII: 4-5
FF IX: 3-5
FF X: 5-5
FF X-2: 3-5
FF XII: 4-5
FF XIII: 4-5

How's FFIV battle system generic? It basically invented the Active Time Battle system which is used in most JRPGs.

I'm only going to review Final Fantasies I have played enough to judge. 

Final Fantasy VI: 4/5

It has one of the most memorable main villains in Final Fantasies, great main character, art style, story, music, well, it's almost a perfect JRPG. A true masterpiece.

Final Fantasy VII: 5/5

Sephiroth, Nanaki, Reno and Rude, Vincent, the whole cast, except maybe Cloud, who is not exactly mister personality, but he is ok. The music in Final Fantasy VII are absolutely terrific, the gameplay surpasses all life, the story is to die for, and the graphics were at the time the best ever. And still are.

Final Fantasy VIII: 3/5

Squall you emo loser. Go and die. We hate you. Junction system was deep but way too complicated. The score was way worse than in FF VII. The cast was interesting, but it feels more like a diamond in the rough when compared to Final Fantasy VII. Graphics are absolute stunning. Gunblade. Triple Triad.

Final Fantasy IX: 2/5

Some of the main characters sucked, both their design and writing, though at the same time some of them are masterpieces that should have deserved a better game. The art style has it's moments but overall it's not that great. The battle system is very oldskool and uninspired. It also ruined Triple Triad.

Final Fantasy X: 4/5

It's a bit too linear, but it still managed to hold on to that sense of an epic exploration through the vast and beautiful world of Spira. The world and its history are well written. Likable cast of characters, except Tidus, made a major difference. Blitz off! The best minigame in a video game EVER! The score also blew my mind.

Final Fantasy X-2: 3/5

Great battle system. It ruined Blitzball and gave some stupid coin game. The story wasn't anything special, but it still managed to grab a hold of the player. Spira was still there and better than ever.

Final Fantasy XII: 6/5

Battle system was magnificent and revolutionary. The best battle system in a video game ever. Gambits, man, gambits. There was tons of things to do and places to explore. The story didn't include needless melodrama, and focused on what was happening on a big scale, the political conflict between two major powers. The characters were great, especially Balthier, but the main character Ashe and Basch really shone through that supernova that is known as Final Fantasy XII. The game that the universe was created for. Words alone cannot express how moved and astonished I was and I still am by Final Fantasy XII.

Final Fantasy XIII: 1/5

Major disappointment. I loath and hate what has become of my beloved Final Fantasy. Sazh alone could not save this game from being an abysmal disenchantment. This game has two of the most annoying video game characters I have ever come across, Hope and Vanille. Especially Hope. I feel bad for the developers and other people who have had to put up with a character so annoying. The story is almost nonexistent, or rather indifferent. The score is forgettable, except maybe the battle theme that rocks. Most of the characters are, regardless of all the back-story, paper thin. Trying to make Snow a serious character instead of a joke character, that he could have been successful at, was a grand mistake. The style is very unoriginal. The game is as a whole a major setback, eminently after Final Fantasy XII. The battle system was ok, but not what one might expect after Final Fantasy XII's marvelous gambit system.

Good night, sleep tight. I'm going to bed. To dream of Final Fantasy XII.

As much as I love FFXII, how was the battle system revolutionary? It's basically a MMORPG system on a FF shell. Plus, the game is played a lot better and has much more strategic value and intensity when playing with the gambits switched off.

No FF battle experience has come close to me as fighting Zodiark and Omega Weapon Mk. II using my own strategies and no Gambits xD