BungeeCord or not?

I'm just trying to work out if most people use BungeeCord to have separate servers for each world, or whether people just use Multiverse and put it all on the same server?

So, to make it more simple, here is what I am asking.
Would most people have it like this?

Hub: Server 1
Survival World: Server 2
Skyblock World: Server 3
etc etc, so all on different servers

Or like this:

Hub: Server 1
Survival World: Server 1
Skyblock World: Server 1
etc etc, so all on the same server

Thanks