The BEC 6600 is not a bad receiver although I do not have much experience using them because it was quickly replased with its competing big brother the BEC 2000. I installed a couple of them but switched to the 2000 as soon as it was available. Pal to NTSC conversion was fine but not perfect. You can upgrade the FTA model to a Common Interface for subscription channels via a plugin module to accept the cards in the fron of the receiver.
You cannot go wrong buying a used one.