Hi Luca and welcome.
EDIT: Rainsoothe replied as I was typing this, so I've doubled up on some of what he said (but you can't hear it too many times
).
I had the GB1 on home loan when it was first around.
Maybe because it was the first floorstander I'd tried, but probably because it didn't suit the room - I decided not to buy it.
However, you might love it, with its transmission line bass (I've got the twenty21 standmount).
If you don't already know, speaker sound is very subjective and influenced by the amplifier driving it and its interaction with your room.
Probably not easy for you to try before you buy, but it would be handy if you could.
If you can get a pair for a good price, they'd certainly be worth a try.
I wouldn't worry about the latest speakers being that much (if any) better.
B&W is a good choice too (I was happy with some CDM1-NT for a while).
Say what music sources you'd like and give a rough idea of your total system budget.
There are plenty of people here that will be happy to advise