Look into Wilson Electronics... all of their signal boosting products meet FCC regulations. One of Wilson's dealers has a very good page on their site where they compare Wilson VS The Competition

A dual band kit would be best for any company (I'm looking into one for purchase) because it works for all providers except Nextel.

Unwiredsignal.com is acutally as I write engineering a system for my bosses' mansion.

Do your research before you make a purchase call the company and talk to a representative ask all the questions you need to before you make a decision. I did it, you should too.

Hope this helped
I.T.