i just joined the forum so i don't know what your last experience was exactly with the Blitzsafe HON/AUX DMX V.2X (if that's what you're talking about). I've read some crappy reviews of the Honda musiclink, so my suggestion is to go with an general Aux input. I can only speak about adding the Blitzsafe to my '06 Navi, which has been working out really well for past year or so.
The nav has XM, but i don't use it or have a subscription. There's no interference or problems when i scroll through audio sources, XM1, XM2, CD/AUX etc. Hope this helps.