Use php mass mailer or simply mail()?

Question

I am sending out ~30k email messages.

Each message will have slightly different content.

I have read that using the php mail() function is not a goo

Answer 1

Here is the canonical Stack Overflow response to this question (in this case to a potential spammer, hence the downvotes, but the information in the first answer is spot on)

How to send 100,000 emails weekly?