I have been using #Fastly nearly since their inception, and it is one of the few tech companies that never disappointed me. They are very obsessed by performance and customer service (< 5 minute response time on tickets).
They love the Fediverse and OSS, and are providing a lot of projects (including Mastodon) with a lot of resources.
Their biggest issue? There was no free plan. But this is now fixed 🎉
No excuse to not try the service and see by yourself: https://fastly.com/pricing