I've had a "Mystic" VGA-modded Colour Classic with LC575 board which has been running fine for a decade, and it's one of my most used 68K Macs.  I was also given a "Takky" VGA-modded Colour Classic with 6500 board + L2 G3 which also runs fine, although needs some soldering around the yoke I suspect due to some flickering colours.

Go for it, it makes the CC much more usable and is the resolution it should have been.