AWS Cloud9 lets me pay for a single big honkin ec2 that backs the IDE, has a better editor, browser ssh support—and has a built in option to suspend the “expensive” instance after 30 mins of inactivity.
I loved Cloud Shell but the inability to let me pay for a bigger backing instance or more storage is a real limitation. (One of my commonly worked on projects takes 25 mins to compile on a boost mode Cloud Shell instance, and operates on ~80GiB of data.) Cloud9 is at a real advantage here.
Whoever first integrates Atom, though (all of these seem to use Ace), I think will be the real winner.