sirius XM issues
 

Anybody notice that for new cars American brands seem to have a free trial, whereas Japanese ones don't? Nissan Maxima I got was new, but no trial. Chevy and Dodge had them.

And do Chevys have an issue with sirius XM cutting in and out, where you have to adjust the channel to get it going again? Chevys are worse than Cadillacs (which are still GM, and still have issues but less).

Not rental car specific, but my wife and I have two vehicles that both have SiriusXM. One of them - a 2011 Kia Soul - gets amazing reception and hardly ever cuts out. The other - a 2015 Nissan Frontier pickup - is not nearly as good on the reception and seems to cut out nearly every time I go under a bridge or even if there are trees along the side of the road.

The way I've heard/seen it explained is that part of the difference in signal is whether the radio is a Sirius system or an XM one. Radios that are Sirius branded have better reception because apparently there are more towers/satellites/etc on the Sirius side. XM-branded ones don't work as well because there aren't as many towers/satellites/etc. My Kia has a Sirius radio, the Nissan has an XM one, so this theory checks out in my experience, but YMMV.

I don't have any info on the free trials except I think both of our vehicles came with a free trial when we first bought them, but things may have changed since then.

At this point, there isn't a huge amount of difference between Sirius and XM, even though their networks are still separate (until a few years ago, they used radically different satellite constellations: XM and now Sirius are geostationary from 2 satellites, Sirius previously used a tundra orbit with 3 satellites (only 2 transmitting at a given instant)). The two platforms encode audio differently (Sirius uses PAC, XM uses an early iteration of HE-AAC): XM's is generally considered to offer better sound quality at most bitrates (though I suspect that PAC uses a couple of techniques to make sound quality more gracefully degrade when there just isn't the bitrate available; PAC also seems to handle bass-heavy content better, which explains some historical audio-engineering choices made on the two platforms), and the subscriber authorization schemes are radically different (XM continuously reauthorizes, once a Sirius unit authorizes, it stays authorized until it gets a kill signal).

The longterm plan is to eventually decommission the Sirius network (most of the OEMs have stopped equipping new cars with Sirius units, with Ford being the last major holdout). The SiriusXM-branded radios are essentially XM 2.0. So far the next-generation combined streaming (including Pandora-powered custom channels) and satellite platform (called SiriusXM 360L) is only in the new generation Rams and there's an aftermarket unit available in a few months.

XM puts most of the music channels (and Stern) on one transponder and the rest on another. It's not unheard of for XM units to have issues with one transponder and not the other.

That's interesting. What does the car's own signal processing have to do with it? Satellite radio seems to always sound better on Chrysler/Jeep/Dodge Uconnect systems.