The web editor works with my Arduino Mega, and two red Uno boards from two different manufacturers. I tried the Blink and Analog Read Serial examples on all three. I like the web editor better than the desktop version. I was carrying the portable version back-and-forth from home to work. The portable is SLOW to upload. I mean, so slow, I forget about uploading and go back to working on other things. The web editor is fast by comparison. But the best thing about it is all files are on the Internet. I can pick up where I quit at a different desktop. It was easy to forget the thumb drive on which the portable version was installed at the end of the work day.
I have been experimenting with Arduino since January of this year. I ordered two kits since then and I have been buying interesting parts at various local retailers. I have completed at least 16 tutorials successfully, more than that, involving small variations. I am only at the stage of changing variables in the code, such as LED blink timing, RGB colors -that sort of thing. For anything more complicated I depend on the forum. I visited other forums but the Arduino forum is overall the most active and has many informed contributors. At this point I don't expect to run into problems with the web editor, just wanted to introduce myself.
Welcome and glad you like the web version I know the team do appreciate comments like yours and do work very hard despite having so many other tasks.
It is very impressive on speed and if you add its file locations to your computers antivirus / security white/exclusion list its even faster.
The regular IDE also benefits from some of the web versions development too so don't discount it completely.
Once the ability to add more boards is available and a few more bells and whistles I think it will really shine.