I'm currently using SendGrid and one of my group IPs has been blacklisted by a variety of email providers leading to delivery issues. Sendgrid's process for rectifying this issue seems to be pretty manual and slow. The cheapest plan that provides for static IPs is $90/month which is pretty pricey for an indie SaaS project.
Obviously, I don't expect any companies to focus specifically on low-volume (and therefore low revenue) clients, but I was hoping there might be a provider who is a bit more proactive in dealing with these issues.
I worked at a place that got blacklisted. First I looked up the list we were added to using MxToolbox. The list we were added to did not have anyway of disputing so I put together a list of email best practices for our sales people and it cleared up after about a week.