I've been using Transcrypt for the last few months and am impressed at how well it integrates with JS libraries. But then that was done with intention in the design. I've been writing React+MaterialUI apps in Python and the resulting code actually still looks like the Python I know and love. I did get pulled into the NPM/Parcel world for JS package management & minification, but the build step is relatively painless and Transcrypt has a Parcel bundler plug-in so there's no extra work involved to use it.
The fact that Transcrypt hasn't implemented the full standard library yet hasn't been much of an issue for me so far either. In the very few cases where I was missing something, I just pulled in a JS library in it's place (i.e. deepcopy).
While using Transcrypt this way requires you to understand the APIs of the JS libraries that you use, the code you actually write is 99% pure Python.
The fact that Transcrypt hasn't implemented the full standard library yet hasn't been much of an issue for me so far either. In the very few cases where I was missing something, I just pulled in a JS library in it's place (i.e. deepcopy).
While using Transcrypt this way requires you to understand the APIs of the JS libraries that you use, the code you actually write is 99% pure Python.