If I didn’t carefully read every page about MarsEdit 2 on the “Mac Web,” I feel like I would have missed that MarsEdit 2 is a paid upgrade. While I believe it was mentioned on your own blog (I think with the teasers and screenshots) and some others, it’s not clear from the product page (to me) that this was a paid upgrade from MarsEdit 1.
I don’t begrudge charging for the upgrade and the fee is not unreasonable at all, but the product page only says “Download a 30-day trial” and “Buy now for $30” and “Requires 10.4!” There’s no mention at all of the upgrade for MarsEdit 1 users, and that was an important missing element for me. I did a find-on-page; the string “upgrade” does not appear. Sure, I can click through to the store but why would I do that if I didn’t know I needed to pay to upgrade? :) In fact, I didn’t notice until my new version expired on me.
My suggestion would be to include basic info about the paid upgrade on the product page, or at the very least on the “what’s new” page. Thanks!