Perhaps an unusual question to ascertain peoples comparison to the Ford 53 chassis to the Mercedes Sprinter chassis.
I currently have one of each so this would qualify as an uncommon answer.
Originally I purchased a Winnebago Reyo 25Q. That it was a Mercedes was incidental to the suitability of size and floor plan. For any rational purpose of discussion, it is a class A, albeit a small one.
Eventually it became clear that the chassis sensor suite was unreliable. Check engine light and wheel sensor issues after every other trip gave us zero confidence. I'm not going into detail as these issues are sufficiently detailed elsewhere.
A Fleet wood Flair 26 D in fresh used condition became available locally and I bought it. The Winni was at the Mercedes dealer for extended service and I was weak.
The house quality between the two is NOT comparable in any way other than floor plan.
I am certain that the previous owner bailed on this unit out of frustration because of the build quality of the house. These issues were fixable (and have been). The chassis is crude, heavy, and old tech. All things that I find appealing.
There have been no drive-ability problems except for the well known steering quirks that have very good after market fixes.
So, is one chassis better than the other? As of 2015, in my opinion, no, depending on your tolerance level. The Mercedes handles better, over all, and with better shocks and roll control can be superb. The current new Mercedes sensor suite has had time to mature and I would expect that basic reliability has improved to the point that I might take another chance.
The Ford F53 has been less trouble some from a perceived reliability point of view.
All issues can be repaired if the owner truly wants it. If the owner insists on making the manufacturer warranty pay, maybe not in his/her lifetime.
Honestly, I think either chassis is a good choice under perfect conditions. As of 2015 the edge would go to Ford. The mileage range with an 80+ gallon tank is very appealing over the range of a 25 gallon tank of deisel in the Mercedes. The generator in the Winni was propane and compared to the Flair gasoline unit is inferior. Ride quality goes to the Mercedes, hands down.
Did "the extra money" for the Mercedes buy better quality? In an abstract way, yes. Did it buy better reliability? Hell no.
Does the Mercedes diesel engine out perform the V10? It is very, very good, but depends on how heavy you tow, as to how happy you will be. Neither vehicle will be the slowest one on the road on steeper grades. This will be a personal decision.
At high altitude the Mercedes will probably out pull the V10, and get good MPGs doing it. On downgrades the V10 will manage deceleration much better than the deisel because of the V10 throttle plate giving superior engine braking.
Both engines willingly run to red-line, safely. The deisel is usually quieter up there. Get a set of ear plugs 'cause the V10 runs loud and proud. A sound I would have loved to hear when I was a kid. Now I have to turn my hearing aid down.
Phil