Ya, macs are definitely more efficient with their ram.

I'll have Android Studio open for my main work, Intellij Idea for all the backend work, and Xcode when I need to tweak some iPhone things. (edit: usually it's just 2 of the 3, but sometimes its all 3)

I also mainly use real devices for testing,and opening emulators if all 3 are open can be a problem, and it's so annoying opening and closing things.