I've had a 1084S for a long time, got it originally for my C128. It looks great, except that A) WorkBench is much nicer in interlaced modes, and B) if you boot into PAL on it, the top and bottom of the screen are cut off in WorkBench (though demos seem to look OK). Also, Amiga RGB output is hard to feed into anything but an Amiga monitor... I need to hook mine up to a projector soon and my choices are either composite (eww) or VGA. Hopefully projectors dont have the same issue as LCDs haha.
However if you dont much care how WorkBench looks, an 1084S is a damn fine monitor.
That said, both the A1200 and A2000 with different kinds of internal scan doublers look fantastic on my CRT. Or rather, they look at least as good as when my PC was hooked up to the same monitor, perhaps slightly better color. As said earlier this is a cheap ass monitor that has always been incapable of sufficient brightness/contrast when displaying darker images. So Im sure on a good CRT the display would be excellent. The image is crisp, theres no blurriness or flicker or other visual weirdness. Since you can get CRT monitors for dirt cheap now, it should be possible to get a nice large monitor for the Amiga that dwarfs any original Amiga monitor. (Those maxed out at what, 15 inches?)