Guns and Ammo- their magazine AR15 had an article on flash suppressors, muzzle breaks.
The Vortex from Smith Enterprises was very highly rated, basically the full size model blocked the flash effectively, the shorty version was not far behind.
There were a few others.
As to muzzle breaks, the lot was mixed, as most could not live up to claims. Did they make an improvement? In most ways, yes. But none did the entire job very well. Muzzle breaks are a bit more subjective, as different shooters are looking for and will accept slightly different results.