Mobile webapp with or without javascript frameworks (jquery mobile, etc.)

For a mobile (single page) web app, I am considering the pros and cons of not using any frameworks - jquery, jquery mobile, etc. I am perfectly fine with handling the ajax with vanilla js. Similarly, showing and hiding divs, and handling the html5 history api, can all be done with vanilla js.

I see that the biggest pro is load time, and freedom from dependencies.

The real difference I see is in the look/feel of the ui - the buttons, forms, etc. all appear somewhat retro, and they obviously default back to the inbuilt options of the platform/browser. So while the functionality is identical across all devices, the UI is somewhat different.

I am not sure if this counts as a pro or a con for users.

On one hand, some might find it offputting, while some might welcome the retro look, while the rest might just not bother. I really have no idea.

Any inputs on the topic are welcome.

PS: There is no need at all to support ancient browsers/devices, which was the traditional use-case in favor of jquery.

PS: This is my first posting here, so feel free to suggest a fix for any aspect of the question you feel is broken.