Dedicated IP
A sending IP reserved for one customer.
A dedicated IP isolates a senders reputation from the shared pool. Useful at high volume (1M+/mo) or for regulated industries that need predictable reputation. Below that volume, a dedicated IP can hurt deliverability because mailbox providers cannot build a reputation profile.
reading this as teams choosing a transactional API
Judged purely as an API. What the request contract guarantees on retry, how complete the webhook event coverage is, whether suppressions are readable and writable programmatically, and how much the message log retains when something needs debugging in production.
Applied to dedicated ip, that means weighing idempotency keys, webhook coverage, event stream, and operating track record ahead of the rest, against high-frequency programmatic sends where a missed delivery is a product failure.