Previously:
Garmin Edge 705 (three of them, first two both had USB ports die, the third conked out after seven or eight years of hard use)
Pro and con:
Rechargeable battery. Decent life if you are sensible with backlight and so on (12 hours or so following a track), and can be topped up on the go, happily runs off a USB source with enough juice. Can be replaced without too much bother. But not as handy for replacement as AAs, battery life not a match for eTrex series.
Pros:
Decent screen.
Can do turn-by-turn from GPX tracks. No ifs, buts or maybes. Load it, and you get a nice clear line, forthcoming directions available for preview, clear instructions (mostly) given and there's always the map to fall back on. Successfully used for over 300km…
Easy (ish) to setup.
Syncing with Garmin Connect.
Cons:
Slow, slow, slow to load and setup navigation. Best option I found to load the night before or on the train to the ride (etc), as 100+ milers could take five or ten minutes to load, if you're not recording at the same time.
Water resistance…hmmm. Joystick seems to be a weak point of the waterproofing. The Wetstable FNRttC of 2012 caused it to require repair.
Buttons can and do perish- ended up having to patch up those on my last one.
Absolutely no way of getting data off in the event of malfunction or the USB port breaking. SD card slot is for maps only, no way of changing that.
USB port flap and SD card cover both awkward and at risk of getting lost. Resorted to using tape on mine.
Directions suffered frequent outbreaks of Garminese. 'Make a U-turn' to my mind means 180 degree turns and returning the way you came, not (for example) using a footbridge to cross a major road.
Mounts are problematic, the release tabs kept breaking on mine (lost count of how many I replaced) and I had the Edge go flying three or four times.
Currently:
Garmin eTrex 30x
Pros:
Excellent battery life from AAs, 25 hours plus.
Good screen, better than the Edge.
Decent performance, much faster than the Edge to load tracks and generally nippier in use.
Excellent build quality. USB flap is a robust-looking part of the case, and battery cover is easy to remove and fit but again robust. The SD card is well protected under the AAs. It hasn't been rained on that much just yet but not anticipating problems.
I'd like the option of a start/stop button, but at least you never forget to start recording.
Mount is simple and and appears tough. No release tab to break off. Lanyard as a backup.
Cons:
Turn-by-turn. FFS, Garmin. Why can't I just load a track and follow it like on an Edge? I've tried various methods of setting directions up, and keep ending up with no directions (or they just stop), maps so cluttered with 'help' like waypoints that I can't see the actual track…it's exasperating. I just want either directions that actually work ('beep' and a prompt to turn left in 200ft) or an uncluttered pink line I can just follow. Do the project teams at Garmin not talk to each other?
Inability to use Garmin Connect (etc) to sync automatically. There's a new track. Upload it. Shouldn't be hard. Connect can update software, nothing more.
Track recordings in one folder with tracks you might want to follow, not in a history folder. So when you want to go somewhere, scroll through all your saved rides…
I'll persevere with it, but these annoyances just shouldn't be there.