FFI
+ Great Replayability
- The Elfland section is kind of long and boring

FFII
+ Cool leveling system and story
- Quite possibly the most atrocious inventory system in the series

FFIII
+ Better selection of job classes
- The final dungeon gauntlet is a pain (DS Version - nerfed the game too much)

FFIV
+ The most solid and balanced game in the series.
- It's the Vanilla ice cream of RPGs.

FFV
+ Favorite version of the job class system
- Krile is kind of a Mary Sue.

FFVI
+ Probably some of the most forward thinking game design in the series...
- ...except the game is way too easy.

FFVII
+ Great world design and music
- Wish I could say the same about the plot that crashes and burns halfway through.

FFVIII
+ Squall has the best story progression of any protagonist.
- Shame Ultimecia shows up and kills any potential in the story.

FFIX
+ Vivi is my all time favorite character in the series.
- I wish Zidane and Garnet would quit stealing the spotlight from the actual interesting characters.

FFX
+ Auron and Jecht are fun and interesting characters.
- The most asinine plot twist in the series.

FFXI
+ Quite possibly one of the most interesting world and stories in the FF series proper.
- Good luck finding with the game's atrocious UI and noob unfriendly set-up for quests.

FFXII
+ Great scope for the world and a gameplay system that works in harmony with it.
- Randomized chests, the Bazaar mechanics, and the abysmal item drop rate can all go to hell.

FFXIII
+ Sahz
- Everything else

FFXIV
+ Pretty much looks like how I thought FFXI was going to be like.
- Having to listen to my FFXIV friend's non-stop talking and praise for it.

FFTactics
+ One of the best stories in the series
- The day you realize most of the jobs and customization are superfluus

FFTactics Advance
+ Great story and characters
- Weak customization mechanics and repetitive quests

FFTactics A2
+ Better refinement of FFTA's mechanics
- Still not as good as I would like, also the main story and cast are terrible.

FFVII: Crisis Core
+ I get to play as Zack!
- Genesis

FF Mystic Quest
+ So bad it's good
- Makes me yearn for vanilla RPG FFIV.

FFX-2
+ Cool ideas for customization system and combat.
- Ideas were handled better in other games, also having to put up with Yuna and Rikku

FF Crystal Chronicles
+ Really cool concept for a multi-player FF.
- Learn which of your friends are selfish bastards.

FF Dissidia
+ Fanservice, oh my the fanservice!
- All that grinding...

FF Dissidia Duodecim
+ I finally get Kain! Also the UI is vastly improved and I actually have a world map!
- The new content makes this more of a director's cut than actual sequel, too much focus on Lightning, the rebalance was not so great.

FF: The Spirits Within
+ Not a bad story when you look past the films non-FF feel.
- Uncanny Valley galore...

FFVII: Advent Children
+ Cheesy crazy spectacle good for unwinding and shutting off your brain.
- the "shutting off your brain" part from above is pretty much a requirement to actually enjoy.

FF: Legend of the Crystals
+ Hey, it's an FF anime! And it's actually a sequel to game that hasn't been whored out by Square yet!
- Calling it an FF anime might be a stretch, also the characters and pacing are not good.

FFXII: Revenant Wings
+ A decent "baby's first RTS" that tries it's best to work with the DS' UI.
- WHAT THE HELL DID YOU DO TO FFXII!?