The chroma bug is an error in the way progressive-flagged material has its chroma channel upsampled in the MPEG decoder.
Here's an article about it (written by me) that covers it in some detail:
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As to your question, I have an iScan pro, and it's a good solution, and allows you...
Personally, I'd recommend a Panasonic. They have the best MPEG decoder for interlaced output right now, largely because they don't have the chroma bug. The RP-91 in the US is excellent, but I don't know what the equivalent is in the UK. The RV-32 is a fine unit, not quite as good as the RP-91...
I also have a Sony VW10HT, and I wouldn't recommend the Denon 2800, as it has a pretty visible chroma bug. Since the 10HT can natively handle NTSC and PAL with no problem, you just need a player than can output PAL as PAL and NTSC as NTSC; you don't need transcoding. Given that, your options are...