I have an OSSC. It works best with a PAL Amiga and the OSSC SCART input. The OSSC's VGA input will accept a signal from the Amiga using an RGB to VGA adapter although the results were less than optimal in my experience. As long as you do not care about any of the higher sync screenmodes (like DblPAL, DblNTSC, Multiscan, etc.) you will be fine. I was a bit put off by interlaces screens at first but then I remembered it was much the same on a real CRT. When interlaced screens are used in games or demos, they generally look very good. I believe this is because the programmers knew to avoid certain color combinations which might exaggerate the flickering. With the TV I am using it on (Vizio M60) there is an unfortunate loss of HDMI sync when switching from high res to hi res laced screens. I do not think it is a fault of the OSSC. My Workbench screenmode in this setup is a simple PAL Hi Res with overscan and it looks very nice.
With the right monitor and a lot of patience, it is possible to achieve some interesting screenmodes. See more about it here:
http://eab.abime.net/showthread.php?t=84788