Performance wise they're probably fairly similar.
The VR-4 is fairly difficult to get massive power gains from, the standard ECU has yet to be cracked (although some very clever people are working on it right now) and the 2 small TD-03's boost early, but don't give massive peak power.
Fuel economy - erm... not particularly great! Around 18mpg around town, and up to about 25mpg on a sensible run.
Manuals are more frugal than the tiptronic, but are rarer. The Tiptronic is a very good box (partly designed by Porsche!) and has INVECS-II, which learns how you drive, and adjusts the gearbox to suit. If you're hooning it, it'll hold the gears for longer, if you're driving sensibly it'll upshift quite early.
Servicing: the VR-4 has very short service intervals - every 4.5k miles!
This is engine oil/filter (fully synthetic only) and AYC fluid in rear diff (Mitsubishi SP-III or equivalent (which includes Hyundai SP-III and Amsoil "Universal" ATF).
Auto box, transfer box, diff oil every 45,000 miles, along with spark plugs, cam belt etc.
They're NOT cheap to run and service, and you have to be aware of that before you buy. Don't skimp on servicing, and you'll have a reliable car which will serve you well!
If you want to know what a VR-4 is like, contact someone on ClubVR4 who's in NZ and see if anyone's nearby who will let you have a look around theirs
Garry