Folks are always looking for fairly objective analysis of one round against another. While it is impossible to perform a truly apples to apples comparison when dealing with different rounds, the comparisons can at least be thorough enough to help someone decide which caliber to go for.
What you shouldn't expect to find in these articles is a clear-cut "This is a better caliber than that" answer. It will almost never happen, because there is almost always something better about one caliber vs another. For instance, 357 Sig may be less powerful than 357 Magnum, but it's pretty close and fits into a semi-automatic weapon's frame readily. Nearly every cartridge comparison will have some advantages to one side or the other.
It's easiest to compare rounds when you have a few set specifications. Wherever possible, intermediate rounds will be compared to the 7.62x51 NATO, lighter rounds to the 5.56mm NATO, and so on. The idea here is that if you wanted to compare, say, 6.8SPC against 7.62x54r, you could extrapolate a comparison by viewing the 7.62x51 NATO comparisons to both the rounds you wanted to look at.