Web based software? no thank you.
Did you actually try it?
It's not like it's a web form that refreshes every time you enter some text. It's actually loading the program which runs in a browser window.
I'd say it reminds me of working on a native program on a 2010 Macbook. You notice it's not quite the same as your actual computer but it's certainly usable.
If I'm on someone else's computer it sure as hell beats downloading or syncing a bunch of Dropbox files an then having to clean up after myself when I'm done.