In my opinion, Monster Hunter 4 Ultimate has better tutorials for things like weapons, however the actual gameplay of Monster Hunter 3 Ultimate is easier, especially the late-game content, and it's less grind-heavy. The swimming in 3 can be tricky though.
I personally liked 3 better than 4.
Jumped on Monster Hunter 3 Ultimate for Wii U
Let me know if you're looking for a hunting buddy sometime, I wouldn't mind picking back up my Bowgun for another outing.