I own a 2005 VW Touareg as well. Each vehicle has its own appeal. Comparing the two vehicles is like comparing Lexus to Mercedes. Lexus being the Subaru. Basically for the money you get everything you need and more. Each vehicle has its own technological features that sets each other apart. Bottom line, I am absolutely thrilled with my new Tribeca. Not only is it one of the nicest cars on the road, there is a sense of independence one feels when driving it around. They are not everywhere. I like it that way, it's my little secret.
Interior features, exterior styling. Absolutely engaging in person. It is a lot bigger than you think.
Bigger gas tank. If you cannot improve the 18 average MPG, at least put in a larger tank. I think it's a 15 gallon tank or something; you have to fill up every 240 miles or so. I hate stopping for gas as it is. The Touareg goes 440 miles between fueling; costs more with the bigger tank but it's worth it.