I used it for a project when I was at university. It was appalling to use. Lots of the examples on the jQuery mobile website failed (e.g. weird redirections when closing modals, lots of odd flashing and jumping around).

A few years later I went back to check the examples and they had the same problem.

I built a complete mobile app using jQuery mobile and it was a total disaster as well. I had so many ugly hacks in place just to achieve what any decent SPA framework does out of the box nowadays. To this day I have no idea what the actual purpose of jQuery mobile was, it sucked for single page apps and felt more like a quick way to make HTML pages responsive. Which can of course be achieved with a bit of CSS or one of the many responsive CSS frameworks.

Thankfully the app never made it to production, for various non-technical reasons.

If you have to select a mobile framework today, what would you choose?

I play with Framework 7 https://framework7.io/ and it looks very nice.

Any other suggestions?

I had the exact opposite experience. I found jQuery Mobile to be very cohesive and simple to use. And the documentation was pretty much on the spot.

I had the exact same experience. Performance on Android was horrible!