I've been collecting LPs for about 40 years and definitely find differences among them. It's not ALWAYS related to label, but in general I've found European labels to have a higher quiality. I'm particulary fond of Philips. On the other hand, two of my all-time favorite LPs are from an American company with a tiny catgalog - Reference Recordings. They make some of the best recordings on Earth.
http://www.referencerecordings.com/
TJ
http://www.referencerecordings.com/
TJ