I put them on my sister's '05 sportster 1200 and I think they suck.
1. They are ugly when off.
2. They are a PIA to put on (wrong bolts sent). Had to buy locally and cut down.
3. The bags stick out at the bottom giving them a wing like look.
4. They bounce around on the bike while riding... looks stupid.
5. Her husband ended up bolting throught the quick release system to get them to stop bouncing... again, stupid.
I saw some somewhere that hinged sideways and had a bottom bracket to stabilize. They also quick released. They were more expensive, but after having put the GB on for my sister, I would spend the extra money.
Easy bags here too. I've used the brackets on a couple different bags. Sometimes it's the bag you try to attach it too. If it's not a very sturdy bag it will tend to sag more. Easy brackets has kind of a big flat base plate, but you could also cut up a piece of stiff board or plexiglass that will go the length of the bag; put between the back and the base plate to give the extra support.