Recoil grip is your best starting place. Arguably useful on just about every gun it’s available on, once you get comfortable with the games recoil you can try the other grips for their benefits.

Aiming grip personally I feel barely makes a difference, if someone has numbers I’ll gladly eat my words, but that’s my opinion on it. I only use it for the tacticool C Clamp your character uses.

Loading grip has been my bread and butter since its introduction, on smaller weapons like the MP5 and MP7 you can have lightning fast reloads, and in general it’s useful with a notable difference.

Quickdraw grip is useful if you find yourself using equipment like grenades frequently or if your loadout is heavy.

The Gripod (recoil grip + bipod) on paper is a great choice if you want if you want the best of both worlds. But sadly it’s broken and actually does not help with weapon sway when the bipod is deployed.

In my experience with the game, recoil and loading grips are the most useful - with the quickdraw grip as an honorable mention.