The newer firmware is *much* better, however it will still get warm in a 3G only area as it seems to constantly scan for a 4G network all the while.
The only dropouts I had with the newest firmware were with wifi, whereby anywhere from 10-30 minutes the overdrive's wifi would go deaf, requiring a reboot of the unit to come back alive. After spelunking in the advanced settings with "help" turned on (why isn't that the default?), I found this setting:
If your computer tends to lose the Wi-Fi connection and stops responding, set this field to off.
That solved my biggest problem and I had an uptime of over 40 hours this weekend on my unit, when I finally powered it down to put in my bag.