Of course I have not lived with any of these, just a fellow potential buyer here, but from what I can tell the Zion SRT design has a lot going for it. It is very open and easy to see out of, which I think would make it easier to use as a daily driver. The compressor fridge is really nice because you can just turn it on and load it up right away (which is how we use the one we have now) and it can cool down without any issues. The macerator will let you empty the tanks at home in a pinch if you need to do so. It is one of the shorter class B vans out there - easier to park and drive.
As for the Sprinter - you may want to look around on the Sprinter Forum site and see what others have to say about it. My impression is that it is a very good van, but you pay a hefty premium for the diesel engine and like any MB product the repair costs (when needed) will be a bit pricy. Commercial owners seem to find the total cost of ownership to be on the high side. It has some unique benefits however, so knowing how it fits your personal needs is the best way to evaluate its cost effectiveness.
