I am a huge L-frame fan. I have a 681 PC, a 686-5 3", and 2 686 MG's. I love the triggers, accuracy, quality, etc. I do though, also really like the GP-100's, especially the fixed sight models. I think "blocky" does apply to the adj. sighted GP's but not to the fixed sights. I think they are very well designed. They actually have more of a service or speed six profile. They also have a slightly smaller grip frame that fits my hand better than any other handgun. I only have 2 reasons for prefering the 686's: 1) trigger-I've felt some nice GP's but they have never had that "feel" of a smith, and 2) for defense I think that 6 is fine but why not be able to load 7 in the same size package? (for plinking it make no difference).
Can't really go wrong with either. Which feels and shoots better for you?