how about just comparing how they ride?
It's not always that easy though is it? Can you put a number on a set bike after an hour riding that covers all bases, 74% for that one, 53% that one etc?
Riding on 2 bikes, with similar geometry (there's tons of bikes like the Meta around atm), similar value, similar forks it can be quite hard saying realistically which you prefer after an hour ride. I could tell straight off the bat I didn't like the Trance X (short and tall

light though) but the Orange 5 felt very like the Meta, it weighed about the same, if the cost were the same I'd have had a hard time picking

You can feel the differences, longer stems, different wheelsets, different bar width/rise but that doesn't always make one obviously better. It's very subjective, unlike weight.
Assuming everything else feels the same and the components on both are reliable, a 28lb trail bike will outsell a 32lb one. Odds are it'll accelerate, decelerate and climb better. Assuming the unsprung mass is lighter it'll even hold speed better through the rough.