The Core

Html5 is the shanizzle, depending on your target market.  If they are mobile and the store caters to B2C, then its worth considering an investment.

From here you can do other things, like adding an Android App loader can get you in the Android store, and Facebook's new App store will be html5 based. But turning your html5 into a FB or Andriod App is definitely going to be an easier step than doing everything from scratch.  Its like any other technology...

 - how bad do you need it?
 - when would you like to jump?
 - when do you have to jump?
 - how this all fits into your over all strategy?
 - is this technology 'announcement' a surprise or planned event? (A planned event = everyone gets the same notice = a new API is released, etc. ::  A surprise event = an opportunity to get ahead = an opportunity for OTHERS to get ahead of me)

We've used a few bits - really small stuff.  However that was because it was the best way to achieve something that needed doing.  Would love to have a play myself, but the days of me actually doing HTML seem to be long past.

We'll use it as the need arises. We'll migrate when we need to.