Techie or blog sites... I don't know about that, I have Chitika ads on my http://www.catsupplys.com, not that they pay very well. The admin area is not secure and very buggy IMO. None the less they have appealing ads.
I use Chitika, Clicksor, Interclick & Google. So far Google is first, Clicksor & Interclick next, and Chitika last. Clicksor is the most similar to Google amongst these.
Miva sucks... I know... I use em (for now).
They pay the worst of all the ppc's but they do have a few advantages. For example, you can make the ads appear as if they are part of the site. The unsuspecting surfer will click on a link thinking it is part of the content. Unfortunately you'll only make .01 or .03. Miva is sad pathetic PPC. Have a look at my http://www.xbox360dreams.com for an example of miva in action.
Can you clixor supporters provide additional details?