In 2017 when we purchased, the difference was between the most expensive Gas Class A, the Adventurer and the least expensive Diesel Class A, the Forza.
We liked the much upgraded Adventurer interior of the Adventurer and the lower overall maintenance yearly cost of the Gas chassis. We're happy with our decision. However, the ride quality on a gas coach is not as smooth as a diesel coach. We've put 28,000 miles on our Gas Class A and love it's livability, quality and affordability.
At the time of our purchase the cost difference between the gas and diesel was about $45,000. However, to get a diesel with the same interior build quality as the Adventurer was approx $100K more costly (the journey line).
Things have changed a bit since 2017. WBGO has reduced the build quality of the Adventurer line and improved the build quality of the Forza line. But the price differential is even higher now.
Good luck with the choice. Folks told us to drive the two back to back and we'd know in a minute which one to pick. However, we spend most of our time living in our RV not driving it. So.....
2017 Winnebago Adventurer 37F
2016 Lincoln MKX Toad