I am using CI, but seriously considering a move to ATK4. The SaaS code I build always has to be desktop & mobile accessible, so recent projects have relied on Twitter's Bootstrap layouts to allow a good browser experience, regardless of screen size.
How does ATK4 handle mobile browsers, especially small screen like on phones? Is it really just a matter of the theme you choose with Theme Roller, and if so, are the any themes that are known for a both a good mobile & desktop experience with ATK4?