I had 2 of these from new, returning the first for the second. Both of them exhibited the same fault - namely they hang / freeze during use. They hang at random points, any time from switch-on to several hours later, so very unpredicatble and very unreliable.
They hung / froze regardless of battery type, or whether the Micro SD card was plugged or not.
I updated the software in each of them to the latest - v2.6. No difference.
I can only conclude that there's a bad batch or design problem. Either way, Garmin are not admitting to it.
If it weren't for this, it would be a great unit.