Not really sure what to think about this episode really. I have always liked Christmas specials, but the 6th of December is a bit too early for me to be in a Christmas mood.
Nevertheless, the episode had some funny jokes and a few references to movies such as The Polar Express (hated it) and The Inglorious Basterds (not a Tarantino fan, sorry). What I absolutely did not like, on the contrary, i found it to be disgusting and offensive, was when Krusty was eating his own reindeer and Lisa, otherwise a big green/vegetarian/humanitarian activist, was eating ham.
Another thing that surprised me was the guest appearance of Katy Perry. Do not get me wrong, i found her very attractive, especially in that dress, but i'm just not used to The Simpsons needing boobs and tight dresses to attract viewers. And this was in a muppet-themed sketch which was (probably) meant for kids. And to top it off, a sex joke in the end when Moe kisses Katy's "belly button".
Normally, I would expect that from Family Guy, and be quite entertained by it, but somehow such things do not work for me with The Simpsons.