Easy, are you a big knife guy, or a small knife guy?
Because the full size is good sized. It is fine to me, but I like a big knife.
As I have sold a good number of knives, to a fair cross section of people, I would suggest that unless you are convinced of your need of the large one, or unless you are really set on the large one...
You will probably be happier with the small one.
Most people do not like their pockets filled with stuff, they find it uncomfortable, which suggests the smaller one.
The one exception is if your hands aren't real dextrous, or you have not used a thumb stud all that much, in which case, the smaller one can be a bit harder for some to operate.
Marion