What makes a good app development company in the USA

Maria

I'm researching mobile app development companies in the USA for a project and noticed that most “top companies” lists focus heavily on ratings and portfolios.

I'm more interested in the engineering side.

For example, how much weight would you give to:

1. Long-term maintainability
2. Linux/backend and cloud experience
3. Security
4. Scalability
5. Flutter or React Native expertise
6. Post-launch support
7. Experience with AI or complex integrations

Companies like GeekyAnts, Goji Labs, WillowTree, and others show up across current industry lists, but rankings vary quite a bit depending on the criteria.

If you've actually worked with an app development company in the USA, what made you choose them and would you recommend them today?

I'm especially interested in experiences from developers, founders, and technical leads rather than agency marketing claims.