I see alot of threads on here about which sling attachment point to get and then there is the issue of stock not collapsing fully or you have to disconnect the sling to switch sides.
I have the Stark grip with built in sling attachment and love it. The grip is solid and has a built in trigger gaurd. The bottom has a plug that will hold either 2x CR123 or 2x AA. The sling attachment is very sturdy and can come either fixed or swivel.
The sling attachment is low enough to collapse the stock fully and not interfere. It also makes transitioning from strong side to weak side very easy and fluid.
The only drawback that I have found with this grip is the bottom plug with battery holes is very tight and not very glove friendly.
Just my 0.02 worth and thought it may be of some help or just another option to look at when looking for a tactical sling mount.