When we switched off of AppSignal, since our instrumentation as deeply intertwined with our code, it took a while to change that over to Otel. But at least now, being Otel, theoretically if we want to change it to a different vendor, we can. If we were to change off of DD, and there is an otel collector that can accept DD APM spans, then we can switch now, refactor later.
In practice, DD has a lot going for it that I don't see in New Relic. There are also some key features in DD that is not in OTEl -- for example, we can't use DD's APM ingestion controls for controlling sampling rates for OTEL spans, and DD has no incentive to add such a feature. I'm actually working on adding in Otel sampling into our project right now. (In our case, we have to use Otel because DD does not have SDKs for Elixir)
In practice, DD has a lot going for it that I don't see in New Relic. There are also some key features in DD that is not in OTEl -- for example, we can't use DD's APM ingestion controls for controlling sampling rates for OTEL spans, and DD has no incentive to add such a feature. I'm actually working on adding in Otel sampling into our project right now. (In our case, we have to use Otel because DD does not have SDKs for Elixir)