Earlier quoted context omitted.
I guess maybe a better way to ask is which acoustic environments do you excel in? In terms of gathering data, I'm curious how to plan to get the 15K audio hours it takes to train each of these models. The most you want to segment it (like through acoustic environment or genders), the more data you need. Do you have a cheap way of generating high quality data?
If you're training from scratch around 10k hours is needed to get a good model, but when you are transfer learning you don't need nearly that much (100 hours gets you a lot). We excel in phone call and meetings settings. I.e. the typical sales/office/support environment.
Mozilla's DeepSpeech is quite interesting, languages like Turkish can get a decently usable (~20% WER) model with just 80hrs of training data (no transfer learning, starting from a clean slate).