My pALS used Model talker when his ability to speak was already a bit affected and while he was recording sentences Google Chrome came out w. an update (I think it was Google Chrome...) and the recording of sentences did not work any longer. He communicated w. the Modeltalker support team and it could not get fixed during the time in which he could still speak relatively well. He then used their process anyway, having recorded about 60% of the sentences and the result was surprisingly good. We all could recognize his voice.
I do not want to give Modeltalker a bad reputation by sharing this. Possibly that could have happened w. different service as well.
When he really needed to use his eyegaze device w. voice software most of his listeners - me included - preferred the inbuilt voice called "Microsoft David" (he had a Surface Pro) as it was much clearer and easier to understand. There were other voices and we had quite some fun with them.
Also, he never really enjoyed his new, medical grade Tobii eyegaze device which after a lot of procedures and hoops was mostly paid for by insurance. It seemed clunky. He preferred much more his self bought surface pro, tobii gaming bar that you can buy on amazon for around $150, plus a software called "optikey" which is free. It did what he needed it to do and provided more flexibility w. a larger keyboard.
Neither one of the 2 setups was flawless. Both needed restarts at times and it was not obvious why. Definitely when the battery was somewhat low but that might not have been the only reason. Sometimes that was frustrating... We were hoping that the medical grade device would be much better and would need less restarts but for his needs and use that was not the case.
Eventually he had the "optikey" software installed on the medical grade device as well and then he switched between the 2 devices - usually 1 would work.