comparing rips for quality

[eezyneezy]

say I want to compare the quality of one music video that I have two different versions of. What I'd like to do is keep the best quality one (taking into consideration filesize somewhat). Other than looking at the bitrates, etc (which I believe means nothing if the rip source itself is garbage) how do you compare video quality between different sources?

is there a program that exists where you can simultaneously play different files at the same time?

thanks!

[futurex]

use media player classic, making sure youve selected vmr9 output. then open 2 instances of it and play each file