Dunno about cost. Been out of the business for a while now. Information Technology pays WAY better than being a machinist (a must for living in the Bay Area), plus costs varies quite a bit depending on your region. Labor in the Bay Area is going to be way more than say, the midwest.
As far as cons, it brings the crank closer to the cam, which does make the chain looser, but any good timing chain manufacturer makes them .005" shorter and possibly .010" shorter. It sometimes can cause issues with the rear main seal.