I've both, SUV and sedan. fuel and tire cost are the two biggies in term of operating cost. Insurance, car wash expenses are slightly higher. Modern AWD system does not need any special regular maintenance, rather just check ups.
I found the S/CUV vehicles, in the entry luxury class, are good high way cruiser, in term of comfort and interior room. They are more capable in the winter months, when equipped with proper tires. Hard to go back to regular sedans once used to an S/CUV, for me anyway.
Enjoy your new MDX, it will provide loads of automotive fun.