What makes a "Chrome book" different from other laptops is the OS. The operating system of "Chrome book" is Google's Chrome instead of Windows or Mac. Most of the applications wont work if you are not online. Most applications and documents depend upon cloud. There fore availability of tons of RAMs or storage space are irrelevant here.
As Chrome book runs Google's OS it will run only Google applications. Users should log in with Google credentials to get the best experience even though you can enter with guest login with limited access.
Getting setup with chrome book is easy if you are experienced with Google applications like Gmail etc.
The processor and RAM will determine how smoothly your system runs. Most of the chromebooks run on Intel celeron processor with 4GB RAM. nVidia Tegra K1 Intel core i3 also started making appearance on Acer and Dell models respectively.
The ideal screen size for Chromebook is around 10-11 inches even though some models up to 15" also available.
Google, Dell, Lenovo, Asus, Acer etc. are the best chromebooks available in the market.