Both locations would be great.... a few points to add about each.
If you fly in on an airline, you don’t need a car once you get to Whistler. Everything is in walking distance, or you can use the free shuttle that does the loop around the village. There is a also a huge selection of condos available in/around the village. This means full kitchen facilities for those that are trying to save a bit on eating out 3 meals a day.
Whistler also has a Heli-port, so if there are any "Full scale displays" this would be a huge plus for any manufacturers interested in doing demo flights. There is also an airport located in Pemberton (25 min drive) for any plank drivers that may attend.
Another point is that there must close to 20 helicopter companies within a two hour drive of Whistler.
The Fairmont at Lake Louise is about a 45 min drive from Banff, it's an amazing place to be sure, but not quite so convient as staying right in town.
Unfortunately there isn’t an airport/heliport in Banff or Lake Louise. There is one in Canmore (only 15 min from Banff) but not really suited for many transient aircraft.
Not sure of the availability of condos right in Banff, although I am pretty sure there is a good selection in Canmore.
Not nearly as many local operators in the Banff/ Calgary area compared to Whistler/ Vancouver.
There are many more considerations of course, I live in Whistler (as you may have guess by my somewhat biased post!!) and am more than happy to help with any questions people have about the area....
DMNH