Stereo Vs. Mono

I have a nice six eye mono copy of Brubecks "Gone with the Wind" and was always hunting around for a six eye stereo version. I recently got my hands on a very clean copy - it would grade NM visually - gave it a good cleaning only to play it and be disappointed with the amount of background noise. The mono version was far superior in every way. I went and compared a few late 50s early 60s stereo with mono pressings and discovered that the mono always sounded better. Since they were early stereo recordings I guess they hadn't perfected their techniques or something. Any ideas? I am still amazed at how mono can have the depth and soundstage that it does. A few times I have set my ARC Ref Phono to mono and forgotten about it getting well into stereo album before I realize that it's still set to mono.