Everyone who promotes a product they use every day doesn't have to be a paid shill. I like PyCharm, DataGrip, and IntelliJ because they generally work very well for me at my day job and open source side projects.

Firefox is an odd case because I've personally never experienced stability issues with it on Ubuntu. The only problem I've had in the past is some Google products are noticeably slower than on Chromium. Colleagues of mine have had stability issues on Windows though.