Between my dad and I we have had several tow vehicles. 02 Malibu, 08 Malibu, 03 TJ wrangler, 07 JK wrangler, 11 Grand Cherokee and now a 14 Equinox.
I can tell you without a doubt the 03 and 07 Wranglers are far easier and quicker to connect and disconnect. The GM stuff wants you to pull fuses and the grand Cherokee has that electronic shifter that frustrates me as you have to have the perfect sequence to get in/out of neutral as well as pull the start button.
I did modify the 03TJ so that a key was not required in the ignition. The newer jeeps (Cherokee and Wranglers) do not require to have a key which is nice.
My dad has the 07 Wrangler and Equinox. He only tows the wrangler if he thinks he will be in places where he wants to explore offroad, otherwise he tows the Equinox. He says he can tell at least a 1mpg difference with his workhorse chassis when pulling the wrangler vs his previous malibu. The Equinox is so new I don't know if there is a mpg difference yet. I do think there is some restrictions on towing the Equinox, like stop ever x miles and run engine but I don't recall the exact details. BTW, we found installing the Demco Base Plate in the Equinox a PITA compared to all the other cars we had, we had to do a lot of modifications. Glad I own a plasma cutter and welder as we used it on the install.
All vehicles had the diodes installed in the tail lights for easy hook up and there was no issue installing those in any of the vehicles.