Voice commands – A killer feature and it actually works pretty well on most models.Garmin probably thought getting into the mobile phone game would just be smooth sailing, but it looks like they've made a deadly miscalculation.

Lane assist – Shows which lane you need to be in for Interstate exits and some surface streets in larger metros.

Speed limit display – 100% of roads aren’t covered, but I typically find that most are.

Found on all current nuvis, but only some discontinued models. It can be helpful in finding your way in unfamiliar areas. This shows up as a thin blue line as shown below.

Track display – See where you’ve been.

Newer models with these have an LM or LMT (the latter includes lifetime traffic) tacked onto the end of the model number.

Lifetime map updates – Garmin has started selling units bundled with lifetime map updates, which you can typically download quarterly.

The one exception here is the nuvi 2×5 series, which allows multiple via points, even though it doesn’t have the other true multi-destination features such as sorting. This isn’t problematic since you can easily find locations under Favorites or Recently Found. If the chart says “no,” you can only enter one destination and one via point.

Multi-point (multi-destination) routing – A very nice feature, but not a critical one.

MSN Direct – UPDATE: MSN Direct services are being permanently discontinued as of January 1, 2012.

I’m a big fan of these, especially when combined with a friction mount. That’s one less connection to fuss with when you want to use your navigator.

Powered mount – The power cord plugs into the mount, rather than the GPS.

Bluetooth for hands-free cell phone use – Generally speaking, the sound quality has gotten much better on recent models, but check the reviews (the first column links to these) as it does vary.

One exception to all this is the 3490LMT, which features ad-free HD traffic.

Most Garmin nuvis with a T following the model number have ad-supported traffic (see reviews for screenshots).

Delivered via FM, this service is provided by the Traffic Message Channel, hence you will sometimes see it referred to as FM-TMC. Expect lots of inaccurate reports as well as incidents that aren’t reported.

Live traffic – A nice feature that isn’t quite ready for prime time.

Speaks street names – Formally known as text-to-speech, this function allows the device to call out the name of the street for upcoming turns, so you’ll get “in one-half mile, turn left on Oak Street,” rather than just “in one-half mile, turn left.” The only current nuvi without this is the 1100 series.

The following, older nuvi models have been discontinued, though many are still available online. Here is our current chart to compare Garmin nuvi models. The following, older nuvi models have been discontinued, though many are still available online and are fully supported by Garmin.

Garmin voice studio for mac