It will more than likely make no difference. Almost all routers transmit at the legal maximum power. They all transmit and receive the data in exactly the same format.
Business equipment generally has features that would not be used by home users. Things like multiple SSID and vlan support and radius support etc. One feature related to power is the ability to dynamically REDUCE the power to allow load sharing of users between groups of AP.
The best solution to a house with thick wall is to use directional antenna. You concentrate the power in the direction of the walls. It is a trade off, you will then get less signal in other directions.
Generally the best solutions to coverage issues is to run multiple routers.
I have a large home with very thick walls. Is it worth paying extra to buy a business grade WAP such as the Cisco Aironet 1041n over a consumer grade router such as the E4200? Any thoughts or suggestions on other routers?