For me the big things are price, ease of use, and data protection policies. I need to know the data never leaves the US, and I need to know what processors will touch it. Then if it meets those needs we'll do clinical demos and tests to get provider feedback. That's where we learn if it is clinically accurate. About half of them suck in the accuracy department.
What stands out to me the most is that the best companies have tended to be the small guys who have a strong grasp ion the entire stack and have somewhat simple apps. They focus on the tech, and have a minimal UI that just focuses on the main tasks and they don't spend engineering time on fancy pretty bells and whistles. If you see a simple UI, that's a good sign to me. Once you hit the big guys the quality goes down. Dragon Medical One is great for straight text to speech, but Dragon with Copilot for medical is really bad.