I work in the aerospace industry and with aluminum and I just want to point out a few things, none of these have to do with any particular bumper on the market. Just want to try and add to the "education" part of this thread.
-You can bend alloys {steel, aluminum, titanium, etc....) tighter than recommended without them cracking (to a point, too tight and they will crack). However, it will induce residual stresses and also failures in the grain structure. This will lead to premature cracking due to fatigue. So if a part is going to see any type of cyclic stress you would not want to bend it tighter than recommended, because the (residual stress + normal stress} * stress riser at the grain defect = crack in very near future. However, if it is just cosmetic and it won't see any working stress then bend it as tight as you can without inducing cracking.
-The tensile and shear strength of 6061 is higher than 5052 (or other 5000 series) and it is harder; however, 5052 has a higher modulus of elasticity and fatigue stress (which allows it to be bent tighter), it will also allow it to be bent further without cracking in an application; however, it will suffer permanent deformation much quicker than 6061.
-If you purchase an alloy in the "O" condition, you cannot heat treat it to T6, just T62. T62 is very close to T6 but it does have slightly lower properties than T6.
-The density of 5000 series is slightly less than 6061 and thus will be slightly lighter.
-Established OEMs will not only utilize regulated design requirements, but also established industry standards and experience when picking a material and designing a part/assy. Thus, experience may show that for production reasons or for part reliability that it is best to increase minimum design standards (like minimum bend radius, material thickness, etc...) to ensure a quality product. This is sometimes also to account for unknowns. It is very difficult to balance lightweight, usability, regulations, and overall reliability without experience. It is especially difficult when you throw in the bean counters and marketing department.
Following is my opinion as related to bumpers or any part for your TJ:
Most aftermarket parts are designed for "looks" or "functionality" with a slight cross-over. I believe it is best to use your vehicle how it is going to be used and then make your purchase decisions based on that use and your check book. I have also found that as you grow or expand in it's use, your requirements will change. So a part that is perfect today, may need to be modified or scrapped and replaced with another part in the future because your use of the vehicle has changed OR you learned something new OR you now have the funds available that you didn't before. Also, hindsight is 20/20, but the only way to be able to look back is to go through the experience and learn, that will allow you to look back and go "oh, now I get it" or "damn, I need to do this before this happens".
This is also my opinion:
Forums - great resource, but use with caution, they are in fact full of opinions and from perceptions that differ. Diverse opinions and perceptions are great, but need to be understood before allowing them to sway your opinion or perception.
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