Well if bang-for-the-buck is your criteria, I don't think the LS1 has it yet. On a purely power to $ consideration, a standard SBC still provides better performance. Only if you enter the weight or coolness factor into the equation do the scales tip in favor of the LS1. An LS1 crate is going to run 5-6K depending upon level of completeness. For that money you get 350hp and 380 lb/ft of torque. Add a cam, or some well chosen bolt-ons and you're getting your 400hp for a few hundred more.

On the other hand you can get the same--or better--power out of a standard Gen 1 crate for a good bit less money, or roll your own for more power and less money still.