Thanks for your report. It seems that several of us are in the same boat. I also am about 30 days from taking a Baltic cruise. I am the owner of a Canon 5D Mk11 and plan on leaving it at home and taking my new NEX 7. I have the kit lens, the SEL 18-200 and contemplating the Sigma 30 2.8.
Your observations are very interesting and I look forward to hearing more.