Any experience out there with the Magnum XM units?

I think you hit the answer in your post, Whatjd. The biggest factor in XM sound quality is the bit rate at which they broadcast the station.

They are going to be merging with Sirius so I think it would be a good idea to wait till the dust settles before spending a lot of money on an XM receiver.

it sure is hard to get any info about these tuners (606) been searching for awhile