I don't have the 7 shot versions, but I have a 4" GP and a 6" 686-1. Both are 6 shot. I've had the 686 for 30 years but always liked the GP too. I could never quite trade the 686 on a GP. Finally bought a GP about 4 years ago. I like both. The GP has a little bulkier frame, but not that much over the 686. Both balance well and shoot well. I've had no mechanical problems with either. The 686's action is smoother, but its 26 years older and been shot significantly more. That said, the GP has a good out of the box trigger. The 686 has a bit more refined finish. Frankly I'm nit picking to find differences and both are pretty comparable.
Since my GP is newer it came with, IMO, awful Hogue grips. I quickly found and installed the old rubber and walnut insert grips. They give a much nicer grip! Ruger's decision to install Hogues was probably cost driven. I'm not familiar with the newer 686 grips. My 686 has the old square grip frame and worn Davis grips since the early 90s. Good purchase and control. The targets are in the 686's box.
In full disclosure I have one Ruger revolver, the GP, and a mix of several N and K frame Smith's.