5.9 Cummins vs 5.3L?

[Skunksmash]

A buddy of mine is weighing the 5.9 cummins vs the 5.3L (or other LS). Guess if the 6.0 LS was a better choice, we'd go with that instead. He wants to put one of those in a K20. The K20 would be a lifted 4x4, so that might put the cummins ahead of the 5.3. Or would it?

So basically, if you were going to buy a k20 and you had the choice between an LS engine and the 5.9 cummins, which one would you choose? And why? What are all the pros and cons? The cummins is going to be a more expensive swap. But it seems to me that when it comes to adding power, which he's definitely going to want to do, the two engines are pretty much equal.