If you collect data (from catalogs or the Internet) for several supplies around 3A to 5A you may see a flattening of the curve. This area probably shows where the manufacturers are competing for the best $/amp ratio, other things being equal.
Then you can see how your two supplies are doing in the whole scheme of things. Outliers
should be disregarded or researched.
Hopefully a bargain will jump out at you.
Then the question of quality becomes important. I doubt that any manufacturer is going to tell you the real value of his calculated MTBF.
I used this method on another forum to rate two cordless electric drills for watts/$, A-h/$ and torque/$. Some parameters came within pennies (~1%) of each other and I do not believe this was a coincidence.
Then another poster came up with a drill that beat the pants off of the first two using the same system and was also rated a Consumer's "Best Buy".