So I bought a Garmin DriveAssist 51 with the dash cam AND a TomTom Go 520. My neighbor who is from England and an IT guy recommended TomTom. The Garmin is a refurb while the TomTom is new. I put them both side by side and drove a few miles tonight, specifically the route where my old Garmin would direct me off the highway to get back on. Unfortunately this Garmin did the same thing, TomTom did not. I’m worried it’s going to direct me down gravel roads again.

This is how I think they stack up otherwise:
Size - draw
Image - Garmin is brighter, white background vs. yellow/brown for TomTom, waiting to check them in the dark
Response time - TomTom seems faster, turns on sooner and seems to reroute quicker.
Voice Activation - draw but Garmin seems to kick on by itself at times for no reason. Garmin is activated with “voice command”, TomTom with “hello TomTom”. Both can be changed to another activation command.
Dash Cam - Garmin only, seems cool, like how it beeps when I got near the center or edge line. Also liked the camera view when arriving at destination. Will need a bigger MicroSd card.
Other Features - pretty even, TomTom has a MyDrive app which can be used to send destinations to the unit. I think Garmin might have this too. Garmin seems to give more street names while driving. It seems as though more things can be searched from the Garmin Voice Commands - restaurants, stores, etc.

Overall actual navigation seems pretty close in the short bit of driving today. Both have things I like and dislike. The Garmin was $147 shipped, TomTom was $173, so $26 for new vs. refurb.