The NAD 521i and 541i are about $200 apart from each other. The value-add of the 541i seems to be a 24-bit Burr-Brown DAC and HDCD decoding, as opposed to just at 20-bit Burr-Brown DAC. As I own about 4 HDCDs, and it doesn't appear that HDCDs are ever going to be very popular, it isn't a major selling point for me. But, how much of a difference is the better DAC going to make? I would love to hear some opinions on this. I've heard the 521i, but not the 541i. The 521i sounds really good, but I might be willing to invest more money if there is a big difference. I am planning on combining this with either a NAD C370 Integrated amp or a c160 preamp and a c270 amp. Speakers are likely to be B&W CDM-1NTs. Does anyone have any thoughts on this?