Honestly, any of them. They're all good. The one I have is three or four years old, and it still works as well as it did when it was new, except for the battery (but it stays plugged in so that doesn't matter). I could easily keep using it for 3–4 more years if it keeps getting map updates. Every few months I plug it into my computer and leave it to update for a few hours (it's a one-click process), but I think some of the newer ones have Wi-Fi so they can auto-update.

It really depends on what features you want. I've found the voice commands to be quite handy. It has a hard time understanding some addresses, but for stuff like "go home", "turn down the brightness", "navigate to the nearest Tim Hortons", it's great. I wish mine had a built-in dashcam like the newer ones, but they're not cheap. Mine has Bluetooth as well, so it can get more frequent traffic updates from my phone (instead of through the FM receiver), as well as take speakerphone calls.

It's pretty much a single function device, which is perfect. I never have to mess with it, it's always there, and it leaves my phone free for audiobooks or for me to use if I'm in the passenger seat.