At the end of the day, and going back to the topic at hand, it doesn't really matter all that much which map is bigger since a lot of marketing fluff used by games companies is often less than completely truthful. Granted its a different company but I think a lot of us remember the history of the promises made about Fable's 2 and 3 as an example of the point I'm trying to make.
I'm not familiar with the Fable series. What happened?
So far, to my knowledge, R* has always been pretty upfront and truth driven.
Hopefully it stays that way.
An awful lot of things were promised about how people would be able to interact with the game world, how big it would be and numerous other things and almost none of them turned out to be accurate.
Its been a while so I'd have to do some hunting to come up with specific examples to be honest but Lionhead aren't exactly unique when it comes to this sort of thing, though they are probably the most blatant
"Cut down a tree, and it's gone forever" they said. Reality - you couldn't cut down a tree. "After chasing some chickens, a random villager called me 'Chicken Chaser'". Reality - EVERYONES starting name was 'Chicken Chaser'. "Open World" Reality - Narrow paths and cells broken up by loading screens. etc, etc,... --- I know what I did was wrong, but they were so pretty.