Howdy mattr69,
So with Calamity's help, I got the ArcadeVGA working with my tri-sync monitor. I wouldn't say that the ArcadeVGA gives 'better' results than a cheap old ATI, but there are certain advantages that are nice to have:
* BIOS boot screen visible
* GRUB screen visible
It took a little bit of finagling -- see my thread 'ArcadeVGA 3000, UEFI, and Nanao 2931' -- but now it works beautifully. It appears to behave just like another ATI card once we get the right parameters passed in via GRUB. ArcadeVGA does make the entire setup process painless, and you have less risk of blowing your monitor because of the bootup sequence driving it at 31.5khz or above.
There's some other caveats that should be fixed in the next release of GroovyArcade like that splash screen being disabled.