The reason I like Jeopardy is that it challenges the contestants both in the studio and watching at home. The questions are very intelligent and require some thought. I consider myself pretty smart and well-educated and I find it challenging. And it's very entertaining. It does not "talk down" to any viewer.
I don't get to watch Jeopardy very often because I'm so busy and don't watch a lot of TV. But we have had the home game for many years -- first as the board game, then as the DOS version computer game and now as the CD-ROM Windows 98/NT/2000 version with all the special effects. I have played this game with my children who are now teenagers and find it very educational. Without trying you can actually learn things about history, geography, music, art, and many, many other topics.
I like the college Jeopardy because it is geared for a younger generation and it is very challenging to the contestants. Middle aged folks like myself may not know all the new hip music and movies. The only variant I don't like is Celebrity Jeopardy because, like "Hollywood Squares" they can be just too cute to stomach. The "Saturday Night Live" parodies are a hoot!
Alex has been criticized by some of the other viewers but he keeps the show on track and on time, not an easy task.
I don't think I'd have the nerve to personally be a contestant on the real TV show, but I enjoy blurting out the answers at home with my family, and I play the home game.
Too many television shows are aimed at the "Lowest Common Denominator" of viewer, but Jeopardy is both entertaining and challenging to people even who have above average intelligence and education. I think it is the BEST game show EVER!!!!