I absolutely loved this episode. Hotch has always been my favourite character, calm, collected, but also a loving family man... and in "100" Gibson absolutely shines. The conversation with Haley brought tears into my eyes. And I'm already looking forward to seeing how he's going to deal with his loss, taking care of Jack and doing his job.
I definitely found the scene of Hotch killing Foyet with his bare hands barely watchable - it practically physically hurt me to see him declining to such a degree. Not that I don't understand him because I do (although I don't condone self-justice - but I've never been in such a situation...). But here, he went against everything he's ever worked (and lived) for, and that's going to take a while to deal with.
Absolutely stunning episode.