Over the past two years one area of frustration for satellite radio consumers has been trying to deal with accounts with both Sirius and XM. A consumer with both services often has to speak to more than one person when dealing with their satellite radio accounts. This has been because the companies, from a customer service standpoint, are still very separate.
Some of this may change in the coming month, or at the latest by years end. Rumor has it that some are being told that there will be a "merging" of customer support within the next month. For consumers this would mean only one call to handle both your Sirius account and XM account. Certainly, given the frustration some have had since the merger will be alleviated. It should also avoid confusion of someone calling the wrong call center altogether. For the company it means a more streamlined process, more satisfied customers, and perhaps a trim in the expense of running two centers.
At this point it is unclear whether billing will be merged. I would also say that it is unlikely that the family plan will translate between the dual service. Perhaps these are issues that will be dealt with at a later date.
Position - Long Sirius XM Radio