Season 1 was mostly a promising start, though with its slow parts and a couple of not-so-good episodes ("Machismo" for me being one the show's low-points), of a show that got better and better until becoming hit and miss from mid-Season 6 onwards.
"The Fox" is one of the season's best episodes along with "Riding the Lighting", in the way that "Riding the Lightning" was one of not many 'Criminal Minds' to reduce me to tears (also cried in "100", "Nelson's Sparrow" and "The Longest Night") "The Fox" is along with "Mr. Scratch", "The Lesson" and "North Mammon" one of the show's most intense and frightening. This said, there are some funny moments too on 'Criminal Minds', with a contender for the funniest being Morgan and Reid's prank war in "Painless".
It is also one of the best written and best in general episodes of the entire show, that is of course from personal opinion. As always with 'Criminal Minds' it is atmospherically, stylishly and audaciously made, and also solidly directed, tautly paced and with effective use of music that's haunting without being intrusive or melodramatic.
As aforementioned, "The Fox" is also brilliantly written, the profiling, procedure aspects and delving into the minds of the suspects helped make Karl Arnold here one of the show's most interesting, memorable and quite frightening serial killers along with George Foyet (the most prolific), Billy Flynn and to a lesser extent Frank Breitkopf). One gets chills with Karl Arnold's dialogue here, some of the most chilling of all the episodes along with the unsub's dialogue displaying his lack of remorse and refusal to take responsibility in "North Mammon" and any dialogue uttered by George Foyet especially in "Nameless, Faceless".
The story takes its time to develop, with a lot of talk and not much action, but still gives us enough absorbing information without bombarding us with too much (a danger with a show that has episodes as short as they are). The crimes, like the unsub, are organised and meticulous, which helps add to their shock value, and the episode is high in intensity and suspense, more so than any other episode in Season 1.
Characters are very well done. Much has been said about Karl Arnold, for good reason, but even so early on the BAU team have personalities very well-established (though JJ becomes more interesting later on) and gel very nicely. Never been a fan of cold and sometimes annoying Elle or Lola Glaudini, but both are fine here. The acting is very good, with Neal Jones exceptional as Arnold.
In conclusion, really fantastic episodes, one of the best-written episodes of 'Criminal Minds' but also one of Season 1's best and one of the show's best in general. 10/10 Bethany Cox