Had one of these fitted at Halfords today. The camera was £130 (£20 off atm) and fitting was £50. When I first used Halfords to fit a dashcam (2017) it cost £25! £50 is a bit steep (recently up from £35), but does include the hardwiring kit. It took the bloke a good hour, so would have probably taken me a lot longer. "Life is too short" and all that. He said that the position of the fuse-box was "not ideal". The dashcam is positioned to the left of the mirror, so you can barely see it from the driver's seat. Not that you need to, mind. I have the screen shutting down after 1 minute anyway. The basic controls (if you need to get into "settings" etc) are definitely easier to use than the ones on my old Nextbase 312GW, which I managed to sell via eBay.
The Garmin 57 camera itself is very 'dinky' (about the size of a matchbox) and works well. The basic features are good, but I had to spend quite a while figuring out how to turn off all the "extras", either because I hate them (e.g. lane departure warning) or have them already (speed camera alert, front collision warning). It also has a limited (24 hours storage only unless you subscribe) "upload to vault" (cloud) feature, which is a waste of time imo. The new thing for me is the (useful) voice control (just say "save video"), so you can quickly save a video (permanently) if you spot trouble ahead. No need to reach for small fiddly buttons. Just need to buy a 128GB micro sd card (£20 from amazon) as the one it comes with is only 16GB. I think a 128 card should give about 6 hours of full HD recording before it "loops". The Garmin app works "OK" but it is not something I can see myself using an awful lot. Easier to just eject the sd card and view footage on a proper (PC) screen.