I don't have much coherent to say about Front Mission 4, so I'll break my thoughts down into pros and cons.

+ Overall solid turn-based strategy game but with noticeable flaws
+ Eases you in before challenging you on your knowledge of game mechanics and builds
+ Good amount of unit customization
+ Surprisingly long game, with over 20 optional side missions
+ New Game Plus
- Rather dry writing and story. The two halves of the story don't really intersect in an interesting way, and the cast of one half has more chemistry with each other than the other half.
- You'll likely hit the same bottleneck over and over while building wanzers.
- You can't look at pilot stats while building wanzers, and you can't look at the pilot's wanzer while going over their personal skills. If you want to go between them, you'll have to sit through two loading screens, or take notes instead.
- The game tells you how far a unit can move but doesn't specify anything about their ability to move to different elevations. One of my units got stuck on a roof because their leg parts wouldn't let them climb down.
- Some side missions need to be unlocked in order and have prerequisites, but they aren't explained anywhere in the game.
- Bonus unlockables also have specific requirements, but you don't know what they are and then they just become missable for the rest of your playthrough.
- New Game Plus is just the same game again but with your stats carried over. I think it could really have benefited from a stage select and the ability to swap between protagonists whenever you like.