I've already gotten feedback from ALL of the people I sent it to! One person collaborates with the person whose study I modeled mine after (let's call him Dr. Bigname), and forwarded my email to Dr. Bigname (who wasn't at the meeting). Dr. Bigname emailed me and said he thinks my study may be the best of its type in Africa! How's that for awesome?! He's forwarding it to Dr. Evenbigger.
As an aside, my poster printed with a minor graphical error that wasn't my fault. I pointed it out to the company who printed it and they offered to reprint it, but when I said that wasn't necessary, they sent me a coupon for 50% off my next poster!
Maybe posters aren't so bad after all.