This article is from the Woodworking FAQ Collection 1, by multiple authors.
There is an excellent article on evaluating carbide tipped
sawblades in issue #72 of Fine Homebuilding (March 1992).
To summarize the article:
An expensive blade will typically last longer than a cheap
blade and the cost difference is made up by the number of
extra sharpenings available from the investment.
A blade that has been tensioned will run truer and cost more
than a blade that hasn't been tensioned.
Carbide blades will last up to 60 times longer than steel blades.
 
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