Overall, I'm not particularly fond of atogs. I like the self-referential
Atogatog, though I always have half-a-moment where I assume it must be an un-card. I like
Megatog, mostly because it was the cornerstone of one of my favorite decks from my early years of Magic (I started playing when Odyssey was out and Onslaught was being released) but also because I thought the evolution of the Atog creature was sort of cool to see, and Mirrodin was the perfect place for it. On that note, I also liked the reprint of
Atog from Mirrodin for its flavor text, for the same reason I really like Mirrodin's version of
Brown Ouphe.