Take a look at the new Leupold Freedom 1-4x20 nice scope I know that someone here on PM had problems with one but I think that was a anomaly.
Nikon has a very nice Monarch in 1-4x20, I think it is called a Dangerous Game Scope/DGR, I've been running one for a number of years on heavy kickers with great results, but the again all my VX- 1/2/II have worked well on 12ga combo guns the only Leupold that I had problems with was an old Varix-II 1-4x20 but I keep it on some light weight predator guns now and have had no problems with it.