The Ultra's don't kick bad at all. I have the Ultra Deluxe in 12 ga. and it handles recoil much better than any pump or auto slug gun I have shot. Then again it weighs a TON. Weight is a very big factor in how a gun recoils and the Ultra deluxes are heavy. They have the heavy barrel, a laminated stock and a steel bar inside the stock to balance out the barrel.
Then you have to throw a scope on it as well

.
I think mine with a scope and sleeve that holds 5 shells weighs close to 12 lbs. Not bad to shoot, but you don't want to carry that sucker very far.
The 20's are probably similar on recoil since they are a bit lighter. Might even be worse with some of the more stout loadings.
I think your going to like it as long as you don't do alot of walking.
I'm thinking of getting the 10 ga turkey barrel for mine.
Paul