Long term reliability I cannot help you with but I can give you some other info if you are interested. This is more than what you asked for, but here goes...
I have a 2013 Mercedes Sprinter with 34K on it. We picked it up Dec 15, 2013. Hit all four corners of the country this summer. Been across I-70 3 times. Been over the Rockies twice and most of the time in between has been going up and down mountains and at least 150 miles have been on dirt roads.
There is no way I would drive anything but a Mercedes Sprinter for that many miles. It may be a big van that weighs 10,000 lbs but it still drives like a Mercedes. I have an MB roadster as well. I won't be taking a sharp curve in the Sprinter at 80mph but otherwise, they really do have similar handling and comfort characteristics. I also have a Dodge truck and an Econoline van, no way I would drive either one of those on a long trip.
The most we have ever paid for diesel is $4.99 and that was in a national park. Otherwise, we are paying about $3.89 per gallon across the country. That is about the same price as Premium gasoline. The low sulfur diesel is the common hwy diesel and is available everywhere we have been except Illinois. If you live in Illinois, MB is not for you because they only have biodiesel 5-20% Your warranty can be voided if you use over 5% biodiesel. The emissions requirements are the same for all diesels, so if you go diesel, regardless of the manufacture, you will have to deal with it. I think MB has a 100k warranty on the emissions system unless you live in California, then it is 7 years, I believe. I think the first maintenance on that system is 60K.
It was my intention to maintain the vehicle myself. MB are EASY to work on, even if the parts are expensive. However, due to being on the road almost constantly since it was picked up I have had to allow others to do the maintenance so far. Maintenance is every 10K unless you are buying 2014/15.
My local Sprinter dealer wants $520 for an A service and $900-1100 for a B service. If you do not want to do the maintenance yourself, buy the parts and find a local to do the maintenance.
-Every 10K you are changing oil $150-$160 to let someone else do it, about $125 to do it yourself (13 quarts of oil at $8.64 at the dealer, cheaper if you can find a source for the oil on sale). Labor cost should be 15-30 minutes.
-Fuel filter is every 20K but some do it every 10K. It is the newest and most expensive one used by the Sprinters, it has the water separator built in. They are $97-$135. $97 is either the Freightliner part price or the mymercedesparts.com price. Labor cost should be 15-30 minutes.
-Rotate the tires every 10k. So far all of my rotations have been free. Don't have a price on what it should be costing. However, you should only have to pay for rotations for your first set of tires. When you buy your next set, you should get rotations free.
Except for tightening the U-bolt at 10k and transmission service at 40k,there is nothing else that needs to be done maintenance wise that you cannot do yourself, easily, even if you have no maintenance skills at all. You will need a $30 air filter from MB and some grease for the hinges. Everything else is look and check for wear. Have not looked at the 60/100k service yet to see if there are any additional items since that is at least a year away for us.
If the cost of the "big" ticket items scares you, buy the extended warranty from MB at $2700 and you will only need to worry about regular maintenance items and traditional wear out items for 125K miles (or 6 years, I think). For most people, that is about the time they are ready for something new.
So far I have had service done in Dallas, LA, Denver, Bangor. Have not had a problem at all finding someone to work on the van. However, if we were to breakdown in some remote area of the country, we know that service may be an issue. So make sure that your roadside assistance covers the cost of towing to a shop that is qualified to work on the vehicle and not just 100 miles or the nearest "shop" and you pay the rest. It is also not a bad idea to get in good with a local Freightliner or MB dealer so that in the event of a breakdown in a remote location, you have someone that will be happy to help tracking down parts for you. The "we can't get parts line" happens on occasion in a busy shop to put you off so that the regulars can get serviced first. Sometimes, there really is a parts shortage. With someone one the inside, you will know what the delay is really about.
Again, more than you were asking for but that is what real world has been for us so far. Would absolutely buy an MB Sprinter again.
