I took the plunge 2 days ago, I had a rock solid 10.7.5 system and was going to stay with it but updated to Mountain Lion to solve a minor problem with DVDSP (see the Cow DVDSP forum for details). I did clone my 10.7.5 system before the upgrade just in case but all FCP apps and others working fine, I did have a problem with ML and eSata drivers. but downloading and installing an older version from Silicon Image (v1.2.5.0) solved it.
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