I have a Philips 107P VGA CRT monitor. HighGfx works fine and looks great for Workbench and OctaMED (gfx artifacts disappear after 5 minutes being powered on). I'm not a gamer so I couldn't give a monkeys about PAL being shifted to the right etc. I have noticed though that with SuperGfx OctaMEDs timing being related to vertical scan goes a bit out of tune. With HighGfx it is fine. I tried it with a Hanng 19" DVI and it worked but it looked too sharp and was unforgiving so I am happy with my CRT.
I really would like an Indivision AGA MkII, but if there's artifacts then that would definitely put me off buying one. Did the MkI have artifacts?