golfnut..........I saw that Jayco has 2 larger units due to be released September/October. They are getting really serious about matching the A classes on the market. We've had Bertha a month and very impressed. I have not done a measure test on my grey/black tanks and for the life of me, I don't understand the grey being smaller either. Good question.
We dry camped 3 days, 2 nights this past weekend. I loaded 2/3 fresh at the house. We showered in the public facilities (very nice state park) but used our resources otherwise. When we dumped as we left, still had 1/3 fresh and both grey and black were 1/3. I know that doesn't offer a close gallon measurement. I'm just saying we could have possibly filled the fresh and showered in our unit...being conservative...Navy shower.
I am going to crawl under and see if I can see a sizable difference in the tanks. They are visible from the door to the sewer hook ups...I watched the fresh fill and the grey is immediately overhead with a heat pad wired to it.
Our focus in searching for our MH was length + slides. We tried to stay under 30' but there weren't many that met our criteria.
We really like our 31 UL and look forward to spending more time in her.
We have 50A, 2 ACs, 5.5 generator, 4 door 12 cu ft. fridge. The entertainment systems are out of this world (for me anyway)......so many options. Watched a DVD on the dinette TV and surround sound. May not sound like much to some...maybe I am easily impressed. Fit and finish very nice. We have put on about 900 miles..........I will be adding a steering stabilizer to settle the wandering....probably a SafeTplus. JRide is a cushy ride not unlike that of a pusher w/air. Of course the pusher has weight to keep things from wandering.
All in all, we are very encouraged.
Darrell