This is probably the highest quality costume I've ever purchased.  I bought one for my 5 yr old daughter, and an adult sized version for myself so we can be a dog pack on Halloween.

PROS:
*Thick and plush material; the dog head is just like a big stuffed animal's head.  Depending on where you live, it'll be nice and toasty in cold weather, but too hot for hotter climates.
*Great quality - the sleeves and legs come with elastic to keep the costume in place.  Zipper is a nice quality as well (adult version), and the kid's version comes with velcro.
*Great visibility - limited visibility masks are dangerous.  Exposing the entire face like this costume allows is the best for a safe trick or treating adventure.
*Cool dog tail - there's a really cool dog tail sewn onto the back.

CONS:
*Sizing runs small, but not a big deal the the kid's costumes.  Just buy a size bigger because the elastic sleeves and legs will help this to fit anyone if it's bigger.  I bought the size 8-10 for my 5 yr old daughter (she's big for her age) and it fits just fine.  The adult costume will be small for taller folks.  I'm 6'3" and this costume gives me an incredible wedgie.  I have to pull up the legs halfway up my calves to alleviate this problem.  I would say that if you're 5'11 and shorter it would fit.  Also, there's plenty of room for the dads with big ole beer guts (of course, that's not me!)
*I bet someone will pull on my cool dog tail.