I have the Arcam rDAC wireless and I personally am rather fond of it, although I normally connect it to my HTPC via a USB cable. In this mode, it's an excellent performer, and you rarely feel that it's diminishing the quality of the music in any way.
In wireless mode, it is similarly excellent, although I sometimes seem to get 'dropouts' (loss of signal) when I am using wifi at the same time. This happens quite rarely, and is not a serious irritant. I recall reading somewhere that it's best to use a dual band wifi system, so that you can avoid running your wifi at the same frequency as the rDAC wireless.
I think it's a good buy, especially since the price has dropped.