Question about Email library and bcc_batch_mode

[eluser]Unknown[/eluser]
Hi,

There's not much documentation about the bcc_batch_mode config. I know that it's self-explanatory, ie. enable batch mode (bcc_batch_mode=TRUE) and set the batch size (bcc_batch_size=100).

My questions:
Does bcc_batch_mode eliminate the need for a conventional Mail Queue, where the mails are sent "silently" via a cronjob? It surely seems to imply this.
What is the best option (mail, sendmail, smtp) for sending, say 1000+ emails when using bcc_batch_mode, and is it rock-solid and robust?

If anyone has experience using the above, your comments would be greatly appreciated.

Thanks in advance