Most of my favorites are under the HG umbrella: Study in Steampunk. Fallen Hero, Wayhaven Chronicles. These are absolute gems of the written word. If you haven’t read these, just… just go and do yourself a favor and read 'em. 
That said, CoG is… safer, for better or worse. The writing is much better, there are no to few punctuation and grammatical errors there, for example. But they all seem to blend together after reading through a lot of them. There’s less risk in CoG, but there’s also less excitement.
I haven’t read a CoG that blew my mind recently.
@Havenstone I’d say part of what makes HG good is the forum interaction. CoG’s beta process is lengthy and there’s a time constraint. As the story has already been written, there’s not much freedom to suggest a drastic revision. You often have to work with what you have. 
But with HG, people come and go all the time. There are a lot of eyes and ears that can collaborate together, making the WIP better than it could have been with a separated review process.