I have seen a couple of "comics" based on the show before, from magazines and such, but they've all been pretty sad affairs; the artwork looked like they'd cut-and-pasted the blandest images from the show they found and slapped speech bubbles on it, and the writing was horribly dumbed-down, with all the character, conflict and mythological monsters from the show thrown out in favor of extremely dull and mundane plots.
Luckily, the IDW comic is nothing like that. The IDW comic is, dare I say it, good.

IDW has clearly banked on this selling by the droves, with a huge number of variant covers; and the pre-orders for the first issue have apparently been bigger than any other American comic outside Marvel/DC. If this is the type of quality they're going to deliver, then as far as I'm concerned the My Little Pony comic deserves to outsell every single DC comic (with the possible exception of Batwoman), because I had more fun and entertainment from the 33 pages of this first issue than I had collectively from the comics I reviewed from DC's new 52.
This comic is a follow-up to the Season 2 finale and includes the return of the villains from those two episodes, namely Queen Crystalis and the Changelings. The issue (first in a four-issue storyline) is dedicated to an Invasion of the Body-Snatchers parody; where every single pony in Ponyville end up replaced by creepy dopplegangers, with the convenient exception of our seven friends -- Twilight Sparkle, Pinkie Pie, Applejack, Rarity, Rainbow Dash, Fluttershy and Spike -- and it's up to the seven to save the day, defeat the dopplegangers and rescue the other ponies. Not the most original of story ideas, but pulled off really well, and used as a set-up to what'll probably be the running plot through the next three issues: A trip to the Land of the Changelings to rescue the Cutie Mark Crusaders, who have typically gotten themselves into hot water again.
The comic is written by Katie Cook and drawn by Andy Price, and both of them deliver spectacularly.
Katie Cook has written a brilliant, action-packed and occasionally hilarious story -- as per usual, Rarity is the funniest character, but all the characters get at least one brilliant moment (the biggest laugh I had here, suprisingly enough, came from Scootaloo). Also, it's very satisfying to have a single comic issue that makes sure that you don't have to wait for the trade in order to get an enjoyable story. Yes, this is clearly the first part of four, but it has its own mini-plot that is resolved and pours on with character development and fun.
Andy Price's artwork is excellent; the look deviates quite a bit from the show and takes a few moments to get used to, but it's energetic, fun and chock-full of little details and in-jokes. There are some marvellous cartoony expressions and lively scenes here that you'd probably never see on the Flash-animated cartoon. Pinkie especially revels in it. (Don't get me wrong, My Little Pony is probably one of the best Flash-animated cartoons I've seen, managing to put in a lot of expression and life -- but this is just on a whole different level.) What surprised me, though, was how creepy it occasionally looked. Don't be fooled by the much cheerier-looking covers; the interiors have black outlines and heavy shadows, and even though the story's all funny and wacky, the images make the Changelings about five times scarier here than they were in the cartoon. And as for Queen Chrysalis...

...yeah.
I'm actually tempted to classify this as a "horror-comedy" story, albeit a G-rated one. Usually, horror-comedies fail at being both creepy and funny, but in my opinion (and this is a review, so if I'm not allowed to state my opinion here, where else?) this issue pulled off both very nicely. Not bad for a comic about pastel-colored ponies and cute baby dragons, huh?
This comic probably panders a little more to the adult fanbase than the little girls (so many memes!), but I don't think there's anything here that should stop the little girls from loving it all the same. If it is a little scarier than the show... well, in my experience, most kids don't actually mind scary stories half as much as their parents think (or maybe the kids in my family have just been very brave). And of course nothing can be too dire when Pinkie Pie is there to laugh at the scary and giggle at the ghostly.

This was a much-appreciated breath of fresh air from the comic scene, and a definite must-read for any pony fan. Along with the excellent Teenage Mutant Ninja Turtles comic that IDW is putting out these days, it really seems like these guys are handling franchises with great competence. Kudos!