There's no interior access to the storage under the sofa, but the space there is twice as big as it is with the dinette. The access is from outside, and goes all the way from the rear of the sofa to the furnace. It'd be nice to have interior access - it could be added easily, I think - but not a big deal.
I really like the sofa. Dinettes are good for eating, but not sitting or really anything else - IMHO it makes the camper much more useable.
I had my 860 for almost 10 years - given the price I paid, minus the trade-in value, it cost me $100/yr.
-Clay