Join Date: Apr 2015
Location: Newcastle Upon Tyne
I think it terms of sheer versatility you might be better off with SMs over GKs. Xabre is spot on with dreadknights though, I regularly go up against two or three of the bastards, but I don't really feel much for the rest of the codex. (Possibly because my winning strategy revolves around killing the damned dreadknights: fun fact, they're NOT fearless)
The obvious fluffy CTs for SMs would be Iron Hands, which I'm surprised nobody has mentioned.
I play Raven Guard personally, which I find are severely underrated and whilst the 7th ed codex change their style of play significantly from 6th, the new Kauyon supplement has added a whole bunch of options / toys.
I genuinely think I've won every game with the Bladewing Assault brotherhood. I don't play in tournaments or anything, but it's definitely a very underrated set up when used to run interference for a shooty army.
Iron hands do get access to Chapter Master Smashfucker though, which is possibly reason enough to go there. It's generally the fluff that keeps me invested when I'm getting my arse handed to me, so I'd go with fluff preference in the first instance.