Great work, congratulations. You just brought q2a theme design to a new level, as it seems to me.
Notes on first glance:
1. I really like the wall design, awesome!
2. nice to see followers implemented on profile page
3. clear and simple tag widget (i prefer simple things)
4. hovering an avatar and having the div poping up, I cannot hover the div, so I don't know (when I'm new) what the icons mean (just later I saw that one is badges, the other one, the star is ..?..)
5. Wow! You managed to implement a dropdown for the main menu!!! ... big respect, I needed a jquery hack to do that. Have you done it without a core hack. if so, you might want to share your solution (really possible by advanced theme? I doubt). great work!
6. on question page: I would give the "best answer" button no check mark but a question mark
7. on question page: maybe don't implement all social share buttons as they give a bunch of extra load to your page, use share URLs instead, see my forum, e.g. random recent post
8. clear post design (q,a,c) on question page. I like the action buttons separated below.
9. maybe reveal the comment always, or just hide it if more than 4-5 lines. Example of what I mean.
10. great that you have an avatar image in front of the "my answer" field, makes it feel human =)
11. others will like the quick login (my users love it too)
12. lovely to see "question badges" with colors, "open", "closed" etc. good and clear design!
- Speed ((as expected, 61 requests, 954 KB, 4.33 sec to load in my setup), compared to my maths site: 15 requests, 405 KB, 1.20 sec)
- main page: could be overwhelming seeing so many faces :) or maybe it's good to have the community feeling (?)
- Tip: reduce load by implementing jquery lazy load, however, that needs some changes in programming (img src becomes img data-original)
- the "read more" button in the footer is not working
- clicking from user profile on "all activities", "all questions" etc. removes the sub navigation on the next page (PS: I have the same issue in my forum and have not found the time and mood yet to solve it ;) )
Hope my feedback helps a bit. Professional work, well done.
And the price, 59.99 USD is more than fair! Guess you could raise it to 79.99 USD. My opinion.
@gidgreen: Congratulations to you as well. You gave the foundation to make all this happen ;-)