Explain, if you will, how the left sucks more than the right.
WMPs UI wins hands down (although the disc data it downloaded off the web was a bit confused... that was a DVD, not a blue ray). I couldn't notice any difference in playback quality (although I'm not usually very sensitive to such issues anyway) however I may not be using the default codec in WMP so that statement may be irrelevant.
Oh and WMP never gives me annoying popups asking me to register...
PowerDVD sucks too.
My opinion on WMP sucking as a DVD player (I don't think it sucks as a general video/audio player), is that in the past I found that for certain DVDs WMP wouldn't allow me to freely move the seek pointer so I had to use the forward/backward buttons, while other players allowed me to freely seek for those particular DVDs.
But note that comment to which you responded was more saying that WMP sucked as a DVD player compared to WMC (though I think WMC probably has the same seeking behavior).
I'm more irritated by above posts praising OSX's DVD playing experience, when OSX's DVD player is garbage, akin to Power DVD. Above it's claimed that an OEM bundling PowerDVD (or some other 2rd party DVD player) would drive a customer to OSX, as if the DVD player that Apple bundles is so much better tha PowerDVD. It ain't. It sucks bad, and has for 10+ years.