I like the fixed 2x leupold on a revolver. It's light and it fits them very well and is a very practical and durable sight. It also covers every hunting situation that I want from a revolver. It has an excellent eye relief and good brightness.
I'm probably in the minority, though. A lot of guys like the 2-6x Bushnell Elites and Burris 2-7x. Generally, I prefer variables, including on single-shot pistols, but in the case of a revolver, the 2x Leupold is king.