I would go with HTML, etc.. First let me say I don't like javascript. That said, we recently built a very nice sales order iOS app (works off line) using kivy (all in python - works on iOS, Android and desktop). I would do it again because I have a python background. But we are now in the process of creating a hybrid app (uses native controls but is still a web app). For the app we are using web components (polymer) with some home grown stuff. Polymer now allows some off line stuff to happen and that works right into what we are doing. It's our intent to write the code in such a way as to allow it to be turned into a chrome app running on a desktop.

Therefore, I encourage you to go with the HTML- etc.

The con:

The web tech in general is moving so fast that you will be in a constant mode of change. It seems that every day a new framework is out trying to be a better way - BTW that's both on the client side and the backend side (yesterday I discovered there is a fork of nodejs). In general it's not a good programming environment. Debugging sucks! The event loop also sucks - it's often difficult to determine the order that things happen. The shadow DOM helps but then again we are just playing tricks. The fact that we have chosen polymer also means we are forcing our clients to use chrome (at least for today).

Speaking of new tech for the web - take a look at 'Dart' and 'go'.

Johnf