Sendgrid is pretty good. I like it's UI and from what I've seen it has feature parity for things like marketing campaigns.
I think it just comes down to using a combination of strategies depending on the need.
Postfix - internal mailing
Amazon SES - One off emails for things like apis where trust/reputation still matter
sendgrid/moosend/etc - marketing campaigns and they also do transactional emails too, I guess. This should be around 15-30 bucks.