Make no mistake: Many of the units out there are the SAME GODDAM ELECTRONICS in a different box. It's like competing Cellphones, they all have similar operating systems, menus and features. Some may have more memory, some may have a better power circuitry, but they are all based on a handful of taiwanese main boards.
Then the subscriber company comes along to a trade show and buys particular models based on exterior design and marketting plans, and the manufacturer begins production on that licenced design, slipping in either XM or Sirius chips to meet the subscriber service.
And they do it based not on provider company, but on models. So that is why Delphi can offer units in both services, and they can cater their units for each other's demographics. Sirius, for instance, licenced the Delphi Sportster, because Sirius makes a metric buttload of money providing Baseball coverage. And the sportster is a lower-model Delphi unit with sports channel pre-encoded.
that's it.
So your only real options with the equipment is your use of it - The Roady units have walkman plugins, to make them like the Myfi, and the unit costs $60 (With another $40 for the walkman unit), changeable display colors (It's the ONLY unit with this feature) and it's an XM device. But if you're a car-only guy (Like I am) you'll have audiovox offering permanent install units that have a half-din display and control unit.
If you own multiple cars, go with something external. Definately. Paying extra for extra units sucks. I have the XR90 with two cradles, for the truck and the Civic. The CRX is getting the Panasonic head unit / Sirius trunk unit combo because I hacked it
-> Steve