The only thing that would be a nice change is the strap isn't very comfortable but on the whole, they work great.
Gives a nice secure grip and feels really nice. Was easy to install and the strap allows me to open my hands up while holding the grips. I particularly like that it has its own battery door so you don't have to take them off to replace batteries.
The plastic thingy that pulls the battery looks like it could damage the inner workings of the controller. I think the best use for it is to pull it WHILE you also push down the battery.
I've been few a number of silicon grips before and most were alright, these however solve two problems! Having to take off the whole grip to access the batteries when they run out. (They come with a built in battery flab), and the grips can sometimes fall off like the stock straps (these have an Index grip design) which hold on tight!
This deserves high praise just for the fact I can change the batteries easily and quickly without having to remove the covers.