It's obviously still pre-final quality. If you need all the bells and whistles the Chrome Web Store is pretty much the same thing (even down to the 10mb limit! for now at least, some games are 90mb) and the CWS has more advanced options and much better discoverability.
But I'm still excited for the Scirra Arcade, it's totally focused on HTML5 gaming so it should be able to hone in and make that a totally optimized experience. Eventually. Maybe when Construct 2 final is released. :O