As far as engine technology, Benz is consistently at the forefront. If you are talking about horsepower, sporty growl, and throttle response, BMW always has the right sounds and feels...
I'll never own a BMW that is out of warranty (and I like BMW's). I've owned 4.
I prefer Mercedes, but when it comes to SUV's I don't care for the ML Benz much.
There was a negative comment on the 2002 Benz E-class. I'm not a fan of the pre-2003 E-class cars. They have been their most popular and best selling models, but to me they are rolling compromises. Go with a C or an S, skip the E. The new Bimmer 745 is still in need of further development (and needs a more traditional BMW rear end treatment in my opinion).
The little BMW 3's are their bread and butter. The X's I've driven have retained a sporty carlike feel which many like.
If I needed an SUV for driving and towing, I'd stick with a GM Trailblazer or fullsize Yukon OR an Expedition or Excursion (overkill for small stuff). I'd shy away from the Explorer and would never consider the Escape. Jeep Cherokee is still a good choice for midsize towing.
I'd not go with a Nissan of any type for towing. The new Infiniti/Nissan uses an unproven transmission technology that I'd prefer to allow others to debug for me.
Toyota offers some rugged tow machines.