AT&T has made deals with a number of car makers in recent years, to bring their 4G LTE network into vehicles. The reasoning for this is to allow users to connect to WiFi once they get in the car, perhaps to save their battery life on long road trips, or maybe AT&T has better coverage in some areas than the wireless carrier you use for your smartphone (doesn't make a whole lot of sense to use OnStar's WiFi service if you don't have AT&T though). We've spent the past week with the 2017 Buick Encore checking out Android Auto, and it is one of the vehicles that has AT&T's hotspot built in. So we've used it to see what the experience is like, and to be honest, it's a bit of a mixed bag. Let's explain.
Connecting to the WiFi Hotspot is actually fairly simple. There are a couple of ways you can get to the WiFi Settings, the one that Buick likes to tout is by pressing the OnStar voice button and then saying "WiFi Settings". But there is also a visual way of doing this through IntelliLink (their infotainment system). Simply go into Settings > WiFi > Manage WiFi Networks and then you'll be able to choose your car's network - which will be something similar to the model of your vehicle. From there if you tap on the information icon, you can see what the password is, so you can actually connect to it. Other than that, it's just like connecting to a typical WiFi network, pretty simple. GM touts that it has a more powerful antenna than a smartphone would, it was tough for us to really test that, seeing as the phone we were using has T-Mobile, and coverage is vastly different between T-Mobile and AT&T. With OnStar WiFi you can connect up to seven devices, and the range is up to 50 feet from the car. So it's a fairly decent range, but really only meant for those actually in the car.
The most important part about OnStar WiFi is actually the speeds you get from AT&T. In the area where we were driving and testing out the Encore, AT&T isn't the best carrier to be using. We're not sure if there are a lot of AT&T customers in this area, or their network just isn't that great, but we typically get very low speeds in this area, and that showed with OnStar WiFi. We struggled to get higher than 1Mbps down, but upload was a bit better, sometimes. There was one speed test where we got about 5Mbps upload, then another where it was just 0.35Mbps. So it's really hit or miss. This really has nothing to do with the car, but more with how good or bad AT&T's network is in the area where you are working or driving. It's not good enough to stream Netflix, which is something that AT&T likes to promote actually, but for streaming music, it should work just fine, and it did for us.
While having your car as a WiFi hotspot sounds like a cool idea, it's really hard to recommend it. Number one, you probably already have a smartphone with a data plan attached to it, so it's hard to justify paying more for a data plan for your car, especially if you aren't already on AT&T. The pricing is also about the same as it would be for your smartphone. You can get 1GB for about $10/month, 4GB for $20 and 10GB for $40. You can also get 250MB for a day for just $5, as well as get a years worth of data (about 20GB) for $150. Which means it's not all that much of an incentive to get 4G LTE coverage on your vehicle. GM and AT&T do offer a free trial of the service though, for three months or 3GB, whichever ends first. Which is a good amount of time to really try the service and see if you need or want it.
As for recommending OnStar WiFi Hotspot to users, I probably wouldn't. Of course, it would depend on your use-case, but for the most part it's just not worth the money. It's a cool feature, and hopefully more carriers add support, so that customers can choose which carrier they want, but being stuck with AT&T is a bit of deal breaker. Especially for those that live in an area where AT&T isn't the best carrier available.