Overture, kanoodle... are they still worth it?
 

with decent keywords becoming rediculously priced are they worth it anymore? What's the average conversion rate these days?

1:20...50 ..more?

average rate depends solely on your overall marketing .. starting with the title and description of your listings

it might still be worth it for some people .. like hosting companies who can make ten even twenty-fold the click cost in a month or two with new customers

but with sponsors .. I don't know, it's expensive and every listings appear to be the same damn thing : sponsors

My personal opinion....the ROI doesn't justify the cost.

The return on investment curve shifts the longer you run the campaign (from my experience). That is, the longer the same ad runs, the higher the ROI, the shorter it runs, the lower the ROI (all other variables being equal)