The Ford is a diesel and the Ram uses gas.
As for a 350/3500 I'd consider one.
The used ford dealer told me the used 250 had a 3.73 rear axle, but I don't that is correct. According to what I've read the diesel came with either the 3.31 or 3.55 rear axle. I'd rather have them say they don't know than give me wrong info.
Also Ford claims that the max 5th wheel towing for the F250 diesel is 16,500 lbs and its max payload us 3120. So do I really need a 350/3500? Don't get me wrong, I'd consider one, I'm just asking. I would think that the 350/3500 ride is more harsh.