AFAIK that will play great, although the quality will not be as good as from RGB signal. The composite by far better than the RF but the RGB is the best. That's why the external sd/ff devices are so expensive. The bad thing is that even with an external sd/ff like Toastscan from softhut you can't mount the miggy to a TFT monitor.
I haven't tried anything of them actually but since I want so badly an sd/ff I asked a lot of people. I believe that this solution is one of the best and most affordable. I ordered from eBay one VGA box but unfortunatelly it hasn't got into my hands :-( ( Fortunatelly I got a refund :-) )
I hope that I helped
