KeithPratt,
From what I've read FCP 7 + SL is all good because they are both designed for 2.2 gamma. Color is a non-issue because it didn't make the same display adjustments that FCP did and if you are using Color you shouldn't be viewing the image on a computer monitor anyway.
JFreak,
FCP 6 and below assumes your monitor is set use 1.8 gamma (which is Mac default except for SL) and adjusts the displayed gamma of footage so it more closely matches a TV screen (2.2 gamma). The problem is if you switch your monitor to 2.2 gamma there is no way to turn the 'auto gamma adjust' happening in FCP off so the footage is displayed incorrectly.
Lethal