Forge:
+ Can customize however you want
+ Not bloated with useless mods/features that you won't use
+ Usually better performance
+ Great for most versions you would use with vape (1.7, 1.8, 1.12)
+ Supported by vape
- Requires a lot of set up to work well
- Finding the right mods can be hard sometimes
- No gui where you can change all of your mods
- Might be worse for performance, it all depends on computer and how you set it up
Lunar:
+ User friendly
+ Usually good performance out of the box
+ Has most mods you would use/need for pvp
+ Works very well with vape (not supported though)
+ One gui to change everything
- If a feature/mod doesn't exist in lunar there is no way to add it
- Filled with stuff you would never use
- Bad performance after playing for a while
- Only really good for 1.8
BLC is basically just like lunar but more features and better or worse performance depending on computer.
Feather Client is like forge but with some built in (pretty clean) useful mods, can be convenient but pretty much every feature in feather can be found as forge mods instead so you might as well use forge.
Also you can use vanilla, if you don't want to bother. V4 already has quite a few good mods that can make vanilla like a small pvp client and since it injects into vanilla just fine its not a bad option tbh. You might want to use it with optifine though, for performance.
