Sentry is not APM, when I last tested the product it looked like randomized tracing comparable to Datadog.
Edit: I looked at the docs, Sentry still has a sample rate parameter so this product can't give you the same results. With NewRelic I can have 100M transaction per day and then I have a single different transaction once every day and I can be sure that the agent will pick it up - always. With sampling you don't get that. Tracing gets you more depth but I seldom need that, I want APM and I only need tracing for a very very low percentage of transactions.
Edit: I looked at the docs, Sentry still has a sample rate parameter so this product can't give you the same results. With NewRelic I can have 100M transaction per day and then I have a single different transaction once every day and I can be sure that the agent will pick it up - always. With sampling you don't get that. Tracing gets you more depth but I seldom need that, I want APM and I only need tracing for a very very low percentage of transactions.