Ok, I ended buying a Garmin 530 as a result of this thread. I used it for several months, and sold it last night. Thinking of getting an Element Bolt V2.
The 530 is a good device and it was awesome for seeing where I was without having to grab my phone, which often doesn't get service in the mountains anyway. The thing is... I learned where all the sanctioned trails are pretty quick, then I didn't need the Garmin anyway. The unsanctioned stuff is where the real fun begins, but it's obviously not on the device, and posting your darkside rides is kind of a dick move so my use for this became pretty limited.
Unfortunately the 530 has quite a clunky interface. 5 buttons, including two up/down buttons, a power button, "yes", "back", and start/stop. Despite all these it makes poor use of them, you are constantly scrolling up and down menus, changing your hand orientation to press yes or back and trying to figure out where you are in the menus. Also, it has a "moving" display and a "stopped" display, so if you look down at your map while approaching a crossroads then stop, it flips to a different map view (north up vs aligned to your movement). Then a GPS error makes it think you started again and it flips back. Surprise! Want to pan the map? Go through a few menus first. Then the up/down buttons act as... up/down. Oh? you wanted to pan east/west? press a different button to change up/down to left/right, then pan. Oh? Want to zoom in? That's right, press the context button to switch modes, then zoom in. Now press it again to go back to panning. It's a pain in the ass. Also the screen/colour/quality isn't great. Think early smartphones from the 2000s.
But... I still had some Squamish and backcountry rides planned, so I kept it around. The trailforks integration will let me easily create routes online, then follow the turn instructions like on Google Maps. Then the panning won't matter, since I will always be on the route, right?
Well not so fast. I ended up creating and saving a Pemberton route on my laptop, then I headed straight to the trailhead eager to get a quick ride in before the forecasted high temp of 39* kicked in (this was in late July). Turned out I didn't have cell reception there. No problem, I can just load the route from the phone to the device right? Wrong. Didn't load. I should have turned back, but didn't thinking I could just make it quick based on my memory. Very wrong. I sweated a lot that day. Yes, it was my mistake for not thoroughly learning how the Garmin works, but It also should be much easier to sideload routes onto a mapping device.
Also, note you'll need two apps for your phone to do the Trailforks integration - Garmin Connect and Connect IQ. Connect IQ is like an app store for your 530, and you need to load the CIQ trailforks app to get the phone and Garmin talking right. It's very stupid.
Other thoughts: the 530 has a propensity for inane bullshit metrics. Every time I ended a ride it asked me how much water I drank, how many calories I consumed before I could finish the ride. What?? the Garmin 130 was so slick, I could end a ride with a few button presses and the ride would be on Strave before I knew it. Now I have to click through several menus of nonsense before it saves. It also makes up a few nonsense metrics of it's own like "flow" and "grit". I have no clue what those are supposed to be and I couldn't care less. It also counts jumps, which seems kind of cool except half the rolls on the shore are jumps according to Garmin. Also it likes to occasionally inform me that I am acclimatized to a certain altitude, and I can track my acclimatization though another menu in the app. I can't wait to never do that.
Overall, the 530 was a step up from whipping out the phone every 30 seconds and trying to keep my fingers dry while swiping and the touch screen. Is it worth the cost? meh, not really. Unless you find cycling more interesting when presented to you in spreadsheet form, at which point I really have nothing to say to you.