I don't have one and never used 1, can you run dual SD cards in it?
Trips and waypoints probably take up bugger all space so can't see the need for a huge memory card for that
Photo's and especially vids, the bigger the better. Looking at the specs its only been tested up to 32GB so if you go any larger than that you may have issues.
As to brand which is better, its sorta like a Nissan VS Toyota debate, pro's n cons on all. I've always used Sandisk cards and never had an issue with them.
Just look for one that has a good read / write speed
If you look through the manual it probably states what they recommend