I've had a Viper, an HHA Kingpin, a Spot Hogg Tommy Hogg and now an HHA Tetra. So far I like the Tetra the best.
All my sights were green .019" single pins. I had an older Viper and it required loosening a screw, adjusting for the yardage and then retightening the screw and because of the design I had to use extensions to mount the quiver out farther from the riser than I liked. The HHA's have proven to be the brightest of the 4 but the Kingpin just seemed too heavy to me. The Tommy Hogg just didn't seem bright enough for me very early and very late and I didn't like the fact that the sight housing itself was simply screwed onto the the horizontal adjusting bar with just one screw....making it susceptible to twisting (rotating) on the horizontal slide. I bought the Tetra about 2 months ago and its super bright, a few ounces lighter than the Kingpin and so far I really like it. Haven't tried a MBG but I hear they are nice.