I agree with drauk; for VFR it cannot matter.
I can think of two things though:
For IFR, there is a lot more to learn in the way of equipment and if one is used to other more basic kit then a G1000 is likely to add a few days to the training particularly if GPS approaches are flown - which they are sure to be if training in an IFR GPS equipped plane in the USA.
Even for VFR, the FAA examiner is entitled to ask the student to show mastery of everything fitted. (I think this is very clever of the FAA because it modernises the PPL syllabus without them getting stick for making training more expensive.) This means loading a route into the GPS, using the autopilot functions, etc. Not a big deal, and unavoidable unless one trains in something completely basic (like most UK training spamcans are) but I wouldn't like to guess how much it will take to teach a PPL student to do all that. It can be quite a leap forward for some people. I've flown with PPLs who have been flying for decades and who wouldn't touch any "avionics" with a bargepole.
In general, I do believe in training in something as close as possible to what one will be flying afterwards. This means you get your PPL and already have many hours on the type. In safety terms, this is priceless.