I think having you be a rabid fan would actually hurt them. Don't take that personally; having our consulting practice be a rabid fan of Basecamp would be equally painful for them.
But if you want to plan a conference booth with a graphic designer, a professional marcom event planning, and some company principals, I can vouch for the fact that Basecamp is awesome.
I'm not even saying they should change them, but for me, there are a few feature changes that would make it way easier for me to use (and therefore a rapid fan and repeat customer).