That is only the raceline bumper, which is in all honest WAY WAY more aggressive when it comes to angle of approach then any of the bolt on bumpers (including their pre-runner bumper which is bolt on). If you are going to be hitting the dunes a lot or doing any aggressive 4x4 and are continually smashing up your skidplate you will not get any solution better then a custom built bumper that requires trimming the frame horns or rpgs race-line (which in effect is a "custom" front bumper that you can order).
If you look at the frame horns where the stock bumper bolts up and look at what the maximum angle of approach is with something bolted to that and the bottom lip of plastic near the grill you can see what you are working with angle wise. You trim off a few inches and redo the angle from the bottom of the grill/plastic to where you could feasible trim from (forward of the mounting point) and you can see that difference in angles.
Chopping frame is not going to be for everyone, but if you absolutely need to get the best angle of approach that is the only way to do it (short of lifting the crap out of your truck and putting huge ass tires on it). But then you would have other problems to deal with, like how incredibly horrible it would drive and look.
I would say for most it comes down to the look of the bumper and how much of a "nose" you want on your truck. I prefer the streamlined look, my complaint about most of the bumpers ihave seen is that they stick out a good 4-7 inches in front. Which when going up a hill some punk jeep owner friend of mine just went up can present a bit of a problem.