What specific features should one look for in an AR flash suppressor before taking the plunge and buying it to ensure that he/she is getting a good/great product?

Thanks for your feedback,

Only one important feature in my book, that it was made by Smith Enterprises: the VORTEX! [;D]

Of course, if you don't like open ended prongs, how about a nice Phantom Flash hider?

If you are going to mount a suppressor/silencer on it, look for one of the QD mounts combos.

If you have a 14.5" barrel, and need to bring it out to 16" minimum legal length (unless it's registered as an MG or SBR) then you must consider length.

The standard A2 flash hider isn't all that good.  A2 is better than the A1 cause it won't kick up the dust and acts like a muzzle brake in a minimal way.

I just don't think you can go wrong with a nice Vortex or Phantom, in that order, but that's me! [:D]

All my rifles either have the Vortex or are getting the Vortex.  Ensure it is specifically a Smith Enterprises Vortex, of recent generation.  There are plenty of cheap knockoffs around.

The flash reduction has to be seen to be believed, and it has a nice twang when the bolt is dropped. :)

Can the Vortex be installed on post bans?

There is one thing that always seems to be overlooked when shopping for flash supression...

How much prone shooting do you plan to do?  If you do a lot of prone shooting, you might want to consider a flash suppressor that does not direct gasses down at the ground like the Phantom & Vortex.  The dust signature and dust flying up is quite annoying.

However, if you do go with a Vortex or Phantom, you can always dampen the ground under your muzzle with water.

The A2 FS does not direct gasses down toward the ground.  Another good option is the KKF A3MSFS.  It's basically an extended version of the A2 and will not direct gasses downward either.  As far as flash supression goes.. it's somewhere between the standard A2 and the Phantom/Vortex's.

KKF = Kurts Kustom Firearms, he can be found in the Industry section of these forums.

No, post-bans may not have flash supressors.

No problem with having flash suppressors up here.

It would seem that flash suppressors such as the Vortex would have most desirable features, but as has been noted - dusk kickup is a problem. Would that someone come up with a design that eliminates that and becomes the best flash suppressor. Hmmmmm....

I've got a Vortex G4.  Fantastic flash suppressor.  Although I can only compare it to the A2, that's the only other one I've owned.  

As a general rule thats true. BUT, if you remove the grip and replace it with the Gogogadgets (ATF approved) vertical grip it is legal to have a threaded barrel/flash suppressor combo on a post ban, because the vertical grip is not considered a conspicuious grip in the eyes of the ATF. ZM weapons has something similar.