Paul and Caz,
Manuals are fine if you enjoy driving them. I used to, but a sport-related left knee injury and the pain of too many traffic jams means Auto gearboxes are the painless way to go - for me, anyway. Now I find the auto makes driving generally more relaxing which is what motorhome touring should be all about.
I've driven manual and auto versions of the same Merc cars, and frankly the weird umbrella handbrake design was either intended for 3-legged mutants, or the designer only had the auto version in mind. I don't know if this handbrake weirdness also applies to the Sprinter cab but if it does I would be wishing I had the auto version for that reason alone. :?
If you are very easy on clutches than perhaps that's a long-term running cost benefit but (touch wood) I've never had to have an auto gearbox replaced yet. I've had quite a few replacement clutches and some problems with manual gearboxes over the years.
A good auto gearbox should have transmission lock-up in top gear so on long trips the fuel consumption is on a par with the manual gearbox version of the same vehicle. The torque converter does mean you use more fuel in urban driving but that's a small price in my opinion.
Anyhow, you stick with the manual ones, if that's what you prefer. All I'm saying is that there's another side to this debate.
SD