Member Rara Avis
Ask how they handle your web logs, Chris. Will the traffic from all domains be lumped together? Does it matter to you? (It probably should.)
As for the shared IP, that is potentially the really big issue. Personally, I don't think a shared IP is a problem with the search engines - if it's done correctly - but I'll quickly add there are some SEO people who disagree. That big "if" depends on whether the configuration is accomplished through httpd.conf or through mod_rewrite. The former is effectively the definition of virtual servers, and I never had a problem getting #1 rankings with a shared IP. The latter, however, can be detected by the spiders and might result in the domain being treated as a sub-domain by the search engines; i.e., low rankings.