Best stroller for 6 months of baby?

So I'd like to buy a good quality stroller for my 6 month old. Right now I have the chicco bravo travel system because he is still in his infant carrier, but I'm looking for when the weather gets nicer in a couple months..so I will only be putting my son in it (no carrier). Everyone says the rubber wheels make all the difference, so I'm definitely looking for rubber wheels only. I was looking into the city mini gt-does anyone have this and like it? Anyways, any suggestions would be great! :)