Sencha is ExtJS merged with jQTouch and Raphael. ExtJS was already a well established company and their core product (the ExtJS library) was worth paying for. I

Sencha is ExtJS merged with jQTouch and Raphael. ExtJS was already a well established company and their core product (the ExtJS library) was worth paying for. I've paid $3000+ for corporate licenses for that library. It really is worth the money if you want a solid JS UI without having to hack jQuery plugins yourself. Now they're extending their core product to work well with mobile devices. I think they'll be able to keep previous customers like me and get some new ones. If you only need a few UI widgets (grid, comboxes, calendar) on your site, you can make do with free plugins and copy-paste code. If you want a solid UI with tons of customizability out of the box, ExtJS is a great option. Now Sencha will provide that and hopefully the ability to write apps for more than one device.