hmmm. i guess if you want it to be able to upconvert/scale video and decode the new audio codecs then it has to be the yammy, since the arcam does none of that, having said that the arcam is still a great bit of kit despite all that,arcam kit has always been able to do both movies and music equally well. but then so can the yammy according to its review. think if it was me i'd probaby go for the arcam still, especially as it under £600 nowadays.
sorry that probably aint much help,but you got me pondering on it now.