If you were towing a lot, I would option for the V8 or 3.0 ED. If not, the 3.6 V6 is a good engine with more HP and equal torque to V8s of just a few years back.
And I don't think comparing a 10 year old SUV that is another brand to a new Grand Cherokee is a fair comparison. Aside from the new technology that the Jeep has, they also have always been superior tow vehicles vs most other SUVs.
Either way, if you already have the trailer, it woudl be a good idea to take it for a test drive towing before you commit.
