I don't think there's an issue as I have been using Spamcop for over a year and forward most of my email to the spamcop account, from various Dreamhost domains.
It's way better now than when I had hosting over at GoDaddy. They were trying to "protect" me by filtering out various emails, some of which were valid and I never knew they had screened by out. That's why I came here - bye godaddy
What plan is best for you? Compare from this list and select the best plan