Unimpressed. I've only just started with SendGrid for my company's transactional emails and already they've placed me on a shared IP which AOL, Yahoo and Sky reject, so my emails aren't getting through to clients with these addresses! They say they can't move me to a more reputable shared IP because it would create the impression of 'Snowshoe Spamming'... well great. Thanks SendGrid. You're an email provider through whom I cannot send emails to a large selection of my clients and you're not willing to do anything about it. Really worth the monthly fee.
