What factors define reliable app development services today?

Hello everyone, we’re a team currently exploring digital solutions and considering different paths for future projects. Our focus is on areas like enterprise mobility and AR/VR solutions, which require strong technical foundations. While researching, we’ve come across a wide range of app development services, but it’s not always clear what sets one provider apart from another. From your professional experience, what qualities or practices do you think truly define dependable app development services in today’s market?