I have one, I think it is truglo... I love it. Biggest tip I can give you is DON'T LOOK AT IT! You will miss every time. When I pull up on a bird I'm looking at the bird, not the sight. You can't miss the sight, it lights up like a 60watt bulb when you pull the gun up. If you look at the duck you will see the sight in your vision, pull the light bulb out in front of the bird and squeeze the trigger.
First thing I noticed when I put it on was that I stopped shooting over/under the birds on crossing shots, I can see the sight better and make sure it is in front of the bird and not in front and up or down.
A lot of people will tell you its a waste of money or that it will ruin your shooting, most of who have never used one and refuse to try it. Give it a try, I think mine cost me $12. Best $12 I have ever spent to improve my shooting. If you don't like it, give it away or trade it to a hunting buddy for a half box of shells.
Why do I shoot 3.5" for geese? Because they don't make a 4" yet!