I have to admit that I haven't really looked at Xinxii until this announcement, and I was prepared to dismiss them for having such a small selection (compared to SmashWords 50+ thousand titles) and the fact they're spending money on an app.
But then there are the details that set them apart from Smashwords. Xinxii let you upload and sell any type of file (including ePUB, Excel, mobi, mp3, PDF, PowerPoint and Word). SmashWords only accept a particular mangled form of MSWord which is then (poorly) converted into a wide variety of formats.
If I want to sell a novel, I'll go to Smashwords. But if I want to sell anything else, I'll turn to XinXii.
P.S. You can get the HTML5 app at app.xinxii.com when it is released.