Most gtk2-based (or dependent, in case of eclipse) apps I use at daily basis (incl. floating deadbeef settings window with older gtk2 plugin) side-by-side. I haven't included evince (gtk3) as I am using partially broken gtk3-Mist theme (not compact as xfce-b5, but still better than Adwaita). Nothing scaled, cropped or such. Btw, I use Classic Theme Restorer plugin, which also helps with firefox UI compactification.