Missing a little bit of email are we? How would you know? You wouldn't and couldn't...but I'm of the belief that php's mail() function goofs up about once every 7 times used.
How do I know? This is my third host and as I casually test my tell-a-friend, I notice the email is not always sent...No error messages, no nothing...it's just not sent. Then, I'll try again after a few minutes and it's sent...Hosts seem to make little difference as this happens with them all. Like I said...I think it's highly unreliable and if you're using mail() for business, I'd seriously think twice...because you'll never know how much mail you're really not receiving. 🙂
As for me, I'll have to find another way...😃