That dude from Mississippi
The 6.0 has plenty of power for 40's. The 6.0's are intended for HD trucks so they have a lot of low end torque, similar if not more than the 6.2's off the line. The 6.0's have VVT and the LS3 does not. This means the 6.0 has great bottom end to get you rolling and at about 4,000 rpm the torque flattens out; then the cam phases and you get a second burst of power.
The truck 6.0's were designed from the ground up to move weight. The lower compression heads, iron block and conservative tuning are meant to make it reliable even when abused or neglected. The 6.0 is designed to run conventional oil and use regular gas keeping operating costs down.
The LS3 shines if you want performance. The non VVT LS3 runs higher compression, aluminum block and high flowing heads. The LS3 is more power than you need for the average JK IMO. I would not say the LS3 is less reliable but it does require better maintenance. The LS3 uses Dexose synthetic oil and requires premium gas.
Bottom line is the 6.0 will easily get the job done. The 6.0 is a workhorse engine that is great in expedition vehicles whereas the LS3 is a high performance Vette engine and a lot of fun to drive.
Great stuff. I plan on a truck motor, when the time comes.