As articulate and agreeable as the above may be to some, it's antithetical to this particular discussion. It assumes that no one is interested in the character of rides, and that all that matters is the amount of work involved. But this discussion assumes that some people have some interest in a certain quality of the work - what it is like, how hilly it is.

In both of the examples (5k' in 50 miles and 10' in 100 miles) the character of the two sounds the same, it's just that the second is longer, but overall, just as hilly as the first. Of course the second is more work, but to anyone interested in the character of a ride, the amount of work involved is meaningless if it's just as hilly as any other hypothetical ride; one could guess as much based on mileage alone. 30,000 miles riding around south Florida may be badass, but for some people it's nothing compared to 30 miles in the mountains.

As for the numbers generally, in that example, they were clearly double each other, so a direct comparison was simple. Now, I don't know how long it takes most people, but even after three years of serious riding, I still can't get a sense of what a ride will be like given x number of feet or meters of climbing, unless it's extreme - like 6000' in 12 miles, or only 200' riding all day long. I have NO sense of where the boundaries of easy and challenging might be when it comes to elevation. The basic unit of measure of whatever is interesting OUGHT to be something one can readily grasp - it shouldn't take years to get a sense of it. I find math interesting, but I'm not very good at dealing with big numbers (scientific notation was invented for good reason). However, I do know that filling an hour with five real hills is serious work, and only one hill, no matter the distance or time allotted, is not going to do me in.

The system that @Machka described is one way of grasping the character of a ride, the result of which is a tidy standard where 1 is the median calculated value between flat and climb-y. This makes sense, because the concern is whether a ride is more or less "doable," or more or less of a challenge, climbing wise - the distance presumably being understood as more or less of a challenge of its own in any case. However, the value is a ratio, not something one can accumulate like miles or km, or understand in the sense of some number of hills.

As for dismissing the altitude data that one may collect based on an uncertainty of its accuracy, that's just sour grapes. Power junkies collect notoriously incomplete, inaccurate data, too, but that doesn't stop them from watching their watts. The point is to come to an understanding of what may be more or less hilly, not to determine whether one has actually climbed some equivalent of Mt. Everest (or can actually power an electric toaster).

As for kidding oneself about who's more badass - if I didn't know better I'd turn that around. If a person doesn't care about hills, that's fine. But certainly a person who climbs the equivalent of Mt. Everest every month is a more badass climber than someone who puts in 1,000 miles on his rollers every month instead. Nobody said anything about who's a more badass cyclist.