I run a limo Co, and my perspective is scewed, of course. We look for dependable serice with minimal downtime for 400K miles.. For Drive For Hire Scenario, based on my and my competitors' experience in the metro area the following is true at the moment:
Lexus LX is the best vehicle for 500K miles of dependable service. High TCO, minimum downtime.
Lincoln Towncar is the best sedan for 400K miles average service lifespan with the best TCO.
Toyaota Avalon is very good for 300K miles, small trunk, best as a one-passenger airporter.
Denali is fine, if you aget a "lucky" one.
Chrysler minivan can run and run and run, if you get a "lucky" one. A good one will outrun Odyssey several times. Depends on the trim and year.
Chrysler 300 - forget about it, too much downtime, not expensive to fix, but too much of suspension and electrical. Brilliant when new, i.e. under 80K miles. Small trunk, but bigger than the Avalon's.
Odyssey - transmission surprises that are still there, otherwise a nice vehicle. Double the AT service frequency and it may do.
Mercedes R-Class is the best for business design wise, but falls apart too soon.
It is a shame the minivans have this idiotic stigma in our culture as they are the best for the business. Especially for the elderly folks. The easiest ingress and egress.
Lexus LS460 is a disappointment after 180-200K miles. The original Lexus was the best.
Genesis and that Horse Dressage uncle are junk in our application.
Audi A8L is superb, but unrelaible.
Mercedes S500 - unreliable.
BMW i750L - unreliable.
Mercedes E-Series Bluetecs - high TCO and too much downtime to make business sense for us.
Some owners have personal Germans in the business part-time to subsides wife's favorite car.
BMW X5 is fine, as one per fleet application.
Acura MDX is very good with family business, when they are shy to pay for a minivan.. if you double the AT service frequency.
Sienna will go for 400K, if you double the AT service frequency.
Expedition is a very positive surprise, no upscale flair though. Not for everybody.