I am a duck hunter in my late 60's. I grew up with a Remington 870 Pump 2-3/4'. I was a what I considered to be a good shot with the old gun. Did and still do a lot of duck hunting. When the steel shot became mandatory, and with the steel shot back then in it's infancy, it was not very effective. I purchased another brand of pump gun, 3-1/2' mag. When trying it out it seamed to fit and point well. The trigger was harder to pull, the safety was in a different place, the drop at the comb and heel were different. I went from a fairly good shooter to almost ineffective. It kicked like a mule. Tried to go back to Remington and could not shoot that either. I bought a Browning Maxus. The safety was in the same place, trigger pull was good, but drop at the comb and heel were different. I was more effective with the Maxus than the pump gun. Since I could not go back to the Remington, I spent a lot of time with the maxus shooting clays and messing around. Starting to shoot decently again. I really like the maxus as it is the softest shooting mag out there. I missed a lot of ducks in the mean time. I am talking about a 5 year retraining.
Find a gun with the same dimensions as the one you have if you can. That it aims down the barrel the same and you won't go through what I have been through. Every one will have a different opinion. If they shoot a certain gun well, it does not mean you will.
There are a lot of different brands and each one will serve someone well.
Hope you pick the right one!