The trade off is higher cost. If you don't put the miles on it, you won't gain anything with the diesel except future towing power. You can put a lot of gas into your truck for a $6k to $8k difference in price. I put over 30,000 miles per year on my truck so diesel is the only way to go or you would be changing oil every 5 to 6 weeks.
Higher maintenance cost is NOT the issue with a diesel, it's the higher initial cost. My diesel has the same maintenance cost as previous gas trucks, I change oil half as often and it costs twice as much. I replace my fuel filters twice yearly ($200 total). Up until this winter, diesel was cheaper than gasoline so I was ahead on that.
If you don't need the tow power or put on some serious miles, it will take a long time to offset the cost. You would likely be tempted to change out the truck before you have even used it up.
I change my trucks every 4 to 5 years after putting on about 160,000 miles (250,000 km). They are still worth some money at that point since it is a relatively new model still. I bought my 2005 in 2007 and sold it in 2012. I bought my 2011 in 2012 and I will likely sell it in 2016 and buy a 2015 or 2016 depending on model year differences.
To each their own and this is just my opinion but I feel unless you are going to put the miles on it you are better off with a newer gas truck. Now if you really want the better economy, try to find a great low mileage diesel that is several years old with a great history.
I'm on my iPhone - I think I just strained my thumb.