I have a Green Mountain Grill and get tons of smoke flavor with it as well as a deep smoke ring in meat but this is at lower cook temps. On higher temps, smoke flavor does dissipate some but is still very noticeable. If you want/need more smoke flavor, you can always look into a smoke tube. I ordered one awhile ago but it still hasn't arrived so I can't really give an honest opinion on one.
Here's a random video review on one.
https://www.youtube.com/watch?v=biJajMAr8ys
I cook virtually everything on the pellet grill now other than steaks. Both the wife and I prefer our steaks seared then bbq'd until done. Can't do that on the GMG.