I've got one of those Rhodesian slings with (Hammer Head Sling Swivels) on my 527 and it's great. I can shoot nice groups on the range with it, and it's easy to use. Took me like 5 minutes to figure it out.
Putting in the sockets for the sling swivels was tricky though. My terrible job takes away from how sleek they make the rifle a bit.