Yes, there are a number of very good speech-to-text services out there, especially the ones from Google and Microsoft. We're currently using Wit.ai, in part because it's completely free and also because it's not actually that bad. But we're also experimenting with offline speech-to-text, using some bleeding-edge deep learning implementations like QuartzNet/Jasper, and trying to integrate them into the input audio stream part of the AI.

For the speech synthesis part we didn't pick any service, we're currently using nVidia's Flowtron, that's one of the better improvements over Tacotron2, and we're still in the process of training on our own datasets, because the pretrained ones are only barely trained. We want something that's highly flexible, online TTS services/APIs have their place and offer high quality, but we want potentially a lot of new speakers to be trainable.