There should be better sites that do this. Most are just skimmers that are trying to rip you off. For auto at least, the progressive insurance site is supposed to be good. I had a chance to meet the Progressive's CEO once and he is a good guy with a good proposition.
As an aside, if you are doing the complete umbrella thing, you might want to price from Ezra Teshome, he does State Farm, but more importantly is a great guy in the community and very honest. We did everything from him before having to move upstream and bigger umbrellas.
He has a family owned business and his wife for a long time (and I believe still does) runs a great restaurant up on Madrona.