Having lashed out on one of these I thought there may be a couple of you out there interested in the outcome - ie is it worth over £500? Well yes, but. Only if you have a high quality display - goes without saying really. You need to try to keep the signal all digital right up to the display - either via a PC then DVI out or a suitable box (Lumagen etc). So how much better is the PQ? Quite a bit better than say an analogue picture via SCART with no processing being done. I was previously using the Sweetspot card and Dscaler to smarten up the analogue feed, and SDI is better but not miles better. I have now sold the Sweetspot card so the nett cost was probably worth it depending on your financial circumstances. But can SDI improve the low bitrate crappy channels on Sky? Actually yes surprisingly. But the real benefit comes from the better channels. The movie channels now approach DVD quality, and the sports channels also are a marked improvement. To sum up, if you have a display with digital input and can keep the signal digital all the way from the dish to the screen, then go for it. And BTW, remenber that the SDI feed comes off before the box can do anything with the incoming signal - I mean anything, including macrovision Not that anybody would need that pointed out of course.