Mio. Better than others such as TomTom, etc. Don't get the no-name unit that's on QVC late at night (my extended, not so smart family bought two of those last year. One was a Cobra, and the other was an Initial brand). We tried to navigate with them on a trip. Both FAILED miserably. Processors too slow, pathetic directions, etc.
I'm told the Mio have the SiRF star III chipset, which locks on fast and holds satellites with an iron grip.
Never used a Garmin automotive, but I rely on a panel mounted one in the airplanes I rent and I have a Garmin 12CX that has worked great. None of those have the road maps, though. I think the Garmins are a bit pricey, but they should work well.
Agreed. I have a Mio DigiWalker 310X. It uses the SiRFstar III chipset, and has a 400mHz processor, so it can't even say it's recalculating before it's ready again. Trip plot takes about 1-2 seconds. Fast little thing.
Also, the interface is a LOT nicer than the TomTom and Garmin look. While the latter two remind me of old Windows setups with lots of dark blue and rectangles, the Mio uses all rounded edges like OSX's Aqua, lighter gradient-shaded colors during the day, and a city-lights blue on black at night. 2D (highway) to 3D (local road) auto-transitions involve a nice spin-and-zoom that lets you keep your bearings if you're looking at it. The hardware shading is pretty impressive for a little device. It's very accurate, the voice is good, too, and when it says turn now, it's right on where you should turn. I like it.
There's newer ones out, too. Also, Mio is a European company, not a Chinese knockoff. They just don't have the mass market penetration here.
Literally the first time I turned it on, it had a satellite lock within seconds, showed the entire constellation it was locked onto and their IDs, and showed current location as "Circuit City, Daniel Webster Highway, Nashua". It's got a lot of POIs. I was rather impressed.