I have only participated in one cover reveal thus far and it was for a book in a series that I enjoy--Georgetown Academy. I was happy to participate in it and it would be something I would continue to do as the publisher/publicist have been great to work with the entire time.
I do think that some blog tours can get to be too long--after a while, I glaze over them because I do not know what other information will be new. I do enjoy reading multiple reviews for new-to-me titles though, so it is a little hypocritical of me to say I get tired of reading the same information on long blog tours. ;-) To me, it is a different case.
What about you--do you like blog tours? Do you participate in them?