How do you measure the quality of app development services?

[harrycollier]

Hi all, we're a small team working on ideas that involve innovative solutions like e learning platforms and healthcare apps. In our search, we've noticed so many providers offering app development services , but most sound the same, making it hard to choose. From your experience, what key factors help you judge the quality of these services do you focus more on technical expertise, user experience design, or the long term support they provide?