My complaints are ongoing not recent. More likely related to interference from cell towers or similar
XM radios have two delivery vectors -
One is line of site to two geosync'd satellites
The other is ground based repeaters to cover areas that would be blocked - city streets, valleys, etc
Bandwidth is relatively low, which is why it doesn't need a dish.
In some cases, an individual building can get in the way if there is no local repeater - they think the area has good line of site.
In other cases, it will work in a tunnel, cause they planned for it.
Sirius has three (maybe 4 now) satellites in a tundra orbit - with a bit of offset, they go north/south, with the earth spinning under it,
the projection is a loop over north america, with two active at all times. The others go to sleep, and recharge as they make a loop over
the southern hemisphere somewhere (too lazy to look it up) - interestingly enough, these are launched out of the
Kazakhstan space port.
The Russian scientists are specialists in this because of the shape of Russia (formerly USSR)
Cool animation here:
http://neilrieck.net/docs/sirius.html