Some statistics about the Season 3 finale in regard of viewers and a summarization of the comic's issue #1 sales have been made.
Summarizing the summarizations:
With the Season 3 finale, the Hub has outdone all the other major cartoon channels for the younger croud, like Cartoon Network, Nicktoons, Disney XD and some more.
Besides, MLP: FiM earned huge percentages in delivery gains among pretty much every age category up to 54. And it seems to be the "most co-viewed network in Kids 2–11 watching with Adults 18–49".
*cough* Yeah. Kids.
The comic's first issue sold rather well in December 2012... Considering only the third printing was counted due to the initial delays. It ranked 12th for IDW's comic releases and 189th in general Top 300 comic sales with 8,605 sold reprints and a total of 95,384 sold copies for issue #1.
For more in-depth information, hit the sources: