I have a 20" spot bar with a 12" flood bar on each side of that. All three bars are mounted on the roof rack. They are single row with 10w leds and are ridiculously bright. I do a lot of logging roads at speed and am very happy with them. The spot and flood argument takes some experience to be a part of. Either a racer or someone who puts a serious amount of miles in the situation where they are needed. The flood patterns are the best for the general population. You will not be able to out drive a good flood pattern of 120w of leds unless you've got a serious amount of suspension. I recently installed Led headlights in my high beam location last week. The following two days I didn't even use my light bars. They won't replace the light bars when on the single lane roads, but they sure did the job on the two lanes and highway.
The other thing about LED lighting is that, due to the vibrant bright white color. You won't need as many watts. Without getting into the details, you are better off being able to have multiple levels of light that one great big bar that is on or off.