It is likely true that an email only provider may have more features. In my experience, the support Dreamhost has provided me whenever I needed it has been exemplary. However, yes, mail is a low priority for them, and I think they focus on just providing the basics (secure, no frills email). They do have a spam filter, but I don't use it.

If you just need the basics: Email addresses, with stuff like SMTP and IMAP support, Dreamhost is more than adequate.