Is there really a value or savings booing airfare through sites like Kayak, cheap o air, etc...Personally I never thought your tickets would be cheaper!

If you are lazy, yes; if you are not lazy, no.

I use those sites to see who has the cheaper flights but then always go to the airline direct to book. Airlines will help you more if there is a problem if you booked directly with them and hotels also. They will tell you know but worked the industry for many years and it is the truth. they hate priceline people most..

Booking sites such as Kayak and so many others can come up with itineraries that combine several airlines which do not normally sell each others' tickets.
Several European sites, notably www.skyscanner.com, find budget airlines North Americans have never heard of. Skyscanner links customers to the airline site itself for purchase at the airline's prices.
The only way to be certain what is cheapest is to check all the possibilities. One rule of thumb can't explain everything; that's lazy thinking.

I have yet to find a better deal, than what I see on the airlines own website. So I stick with that.