I shot a plain old front bead sight for years on my Dad's old J.C. Higgens 12 ga. No snickering at the family heirloom shotgun with the duct tape to hold on the sturdy front stock piece. I lost a lot of front beads too by not being real careful where I swung that barrel. One day I picked up a shotgun that had 2 beads on it and VOILA, not so many misses.
I still had a bad habit of peeking and lifting my cheek off the stock when pulling the trigger, causing me to shoot off a bit sometimes.
About 6 or 7 years ago I put a Leupold 1 X 4 shotgun scope on my Rem 870. Camoed it up and put some Butler Creek scope caps on and zeroed it in pretty quick. I used a B-Square mount on my Rem 870 to mount the Leupold rings and scope.
The only problems so far are the sharp edges of the mount rub your hand when you carry it since the mount sticks out from the side of the receiver. Other problem is taking it off the mount to clean the gun and losing the push pins that hold the trigger in.
The advantages of a scope over beads is you can see the birds a bit closer to look for spurs or beard length. No more misses from canting the gun or lifting my cheek, I put the crosshair on what I want and the shot pattern is centered there. I leave the scope on 1 or 2 power to get a wider field of view. Eye relief hasn't been a problem when shouldering the shotgun real quick.
Remington makes a cantilever mount that goes on the vent rib with set screws. Only problem with that setup is you lose the ability to use your bead sights with the scope on if the scope goes bad. (That cost me a deer one year). You can use your beadsights with the B-square mount with scope on as a backup. Here's what the bead sights look like with the B-Square mount on.
Both are same price, cantilever weighs less, but not as sturdy as B-square in my opinion, and believe me, I've whacked my Leupold hard a couple of times with no problems so far.
Haven't seen any Millet shotgun mounts in the field, just at the gun shows. Curious how they hold up. I looked at both and went with B-Square since they were in stock where I ordered.
I've shot some of the hi-vis glow sights and they worked well, especially in low light. I don't know if those plastic sights would last long on my shotguns though, I'm notorious for tearing up shotgun sights in the field.
I looked at the Busnell Halo sights at the SHOT show and I know some goose hunters who swear by them. The red dot sight are interesting but I seem to lose the red dot sometimes while swinging it around.
One last note on scopes, make sure it's legal in your state to use a scope on a shotgun for turkey hunting, in Alabama the use of a scope is illegal.