There is a trade off to each. What you'll really want is a combination.
The light rack a.) looks badass, and b.) has a lot of mounting options for lights and gear. However, the light out the front will be for distance, overhead and out the sides. The roof will cut off ground light close up.
The bumper lights put a lot of light on the ground with a low profile and simple install, but can be obscured by low branches, tall grass and hills.
If it were me (and, at one time it was) I would go with the light rack with two Whelen Slimlines out the back, and two Whelen Micropioneers in the front bumper or on the hood and a light bar across the rack over the roof.
Fact is, for the price of six Whelens and brackets, you could basically have 4 Whelens (micros and slims are the same price I believe) and the light rack.
To keep in budget, you could have the light rack fabbed with brackets for all the lights, buy them as you can afford them, and just bolt them on.
Food for thought.