World Modelling

I have been working on Softimage XSI for quite a while now, and I would like to know, if there are better software to start modelling worlds than XSI… In my opinion, it’s very easy to operate, but working on large-scale areas, like cities (mostly urban areas) could get tricky as you progress in work. which software could I use to model large urban areas later to be exported as full-scenes for video games?