I'd love to see reviews or performance benchmarks from people who've built using Kivy, but I can't seem to find much recent information. Can anyone help out? Thanks!
The first is the documentation, which while being quite extensive almost never tells the whole story, especially the many paradigms and details which are very different from other frameworks.
Second is how hard it is to even achieve simple tasks (beyond putting a few buttons together). A good example is the almost dysfunctionally complicated ListView, which actually can't do that much. Kivy's widgets in general are lacking, and the visual design philosophy seems to be "ugly by default".
This is really just my opinion. I think that the event and input handling is great, and the graphics library is very remarkable for supporting hardware acceleration to a python app on so many platforms.
About ListView... Let's say it's one of the Kivy widget that doesn't fit to the Kivy logic at all. Historically, i started a POC about it, then a contributor take it and worked a lot to have something that works for any sort of situations. And he tend up to something that cover lot of cases, but still bugs, and not easy to get it. Not to mention issue with performance. That's why i rebooted the ListView from scratch, and named it RecycleView (like RecycledView from android): https://github.com/kivy-garden/garden.recycleview
The visual design was taken from Meego / Android in the old days. We might be able to refresh the theme one day, if we have somebody that can contribute to it (i mean a real designer, not a coder). I rarely use the default theme, always extend a widget to put the designer visuals i got on customers projects.
Started with Swift recently and doing Paul Hegarty's course on Stanford now. Its good, so far!
That was certainly my impression just from looking through the docs. Unfortunately there aren't many people doing cross-platform UI well, especially for games. The few decent open-source options (eg, CEGUI) don't support mobile at all.
http://www.autosportlabs.net/RaceCapture_App_User%27s_Guide
And our app is open source! https://github.com/autosportlabs/RaceCapture_App
Around 50 on the Play Store. Only a handful on the App Store. Also, this list is not exhaustive.
Right now, it seems that peoples are shy to share their apps. We have a list on the wiki of what we have found + users contributions: https://github.com/kivy/kivy/wiki/List-of-Kivy-Projects
But i'm sure there is more. Like this one: https://play.google.com/store/apps/details?id=com.nrtech.nrt... - Kivy is not referenced anywhere, but it's based on it.