I agree that the LS engines are a superior design, all of our fleet trucks are 6.0s and they're awesome, our workhorse truck is a 4 door long bed with a full service bed full to the top with tools, a Hobart generator/welder, 60 gallon air compressor, and 50 gallon diesel tank. That truck never ceases to amaze me how it still hauls ass with all that weight. Just for s and giggles I raced my buddies '95 (VERY good running stock truck but hey, it's still a TBI) and flat out smoked him. That service truck has to weigh three times what his does.
BUT I like being able to reach back into an endless supply of decades worth of GM performance that will all still just bolt on, are much cheaper than LS parts, and can be tuned in without an issue. I'd be willing to bet dollar for dollar I could make that 7.4 whip any LS. Not to mention, you just can't beat the nasty sound of a big block.
That being said, the 6.0 swap is still in the back of my head, because it does still have a large aftermarket support as well as the reliability. Though I doubt I ever will, I'm a Pontiac man at heart, and will have an injected Pontiac in my truck in the future.