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 developers picking email infrastructure
The question here is which one a backend engineer would rather operate. That means SDK depth in the language already in use, whether a retry can safely be replayed, how much the event log tells you when a customer says the email never arrived, and whether the pricing curve stays sane as volume grows.
Applied to dedicated ip, that means weighing developer experience, SDK breadth, idempotency keys, and operating track record ahead of the rest, against password resets, receipts, and magic links shipped from application code.