People need to pay SendGrid at least $80 per month for the silver plan in order to get rid of the (via sendgrid.info) header in Gmail (sometimes people only need to send a few K emails..)

http://support.sendgrid.com/entries/98008-how-to-eliminate-t...

Also, do you support mass newsletters sending to subscribed users? I use sendgrid because many other providers like MailChimp said they don't allow it.

To be fair, sendgrid's service is also very good, e.g. customer support, reliability etc.