I have a Garmin 820. It's a very annoying device. Connection to my smartphone over BT is crap, loading GPX file is a nightmare, and the Garmin maps don't match the actual trail markings where I live.
And guess what - any Android phone can do the above .
So I thought - what if I buy a small android, just for this task? I don't ride in the rain, and battery consumption will not be a problem - the main phone will still sit idle in my bag.
No comments really about the specific device you mention, but I do have some questions/comments.
1. I hear plenty of stories about the terrible touchscreen of the Edge 820. Honestly, I don't like touchscreens on my bike at all. Every single one I've ever used has been problematic in one way or another. I suspect you'd just trade one set of irritations (Edge 820) with another (cheap android device). The worst touchscreen I've ever used while riding was my old Samsung Galaxy S5. That touchscreen went absolutely batshit poltergeist crazy if there was any sweat even nearby. A cheap android device will probably be as bad or worse. The resistive touchscreen on my Oregon 450t doesn't flip out with sweat, but it's nowhere near as precise or responsive. It's minimally functional as such, mostly for just tapping the screen (swiping is just "meh" and there's no multi-finger input options). I've given up on touchscreens for bike computers. Button-only inputs may be annoying in their own ways, but at least they work and are predictable.
2. What is so "nightmarish" about loading .gpx files? I can't say I've had problems with the process before. But then again, I don't find the feature all THAT useful for mtb use.
3. Absolutely ZERO digital trail maps are going to be correct for every place 100% of the time. If you have that expectation, you're going to be disappointed all the time. There are HUGE logistical problems to ensuring that level of accuracy on a consistent basis everywhere. You're going to have to do some legwork to find the best maps for your area. Once you do, you'll find that there ARE better options, but it'll take some extra steps to update your device with those maps. And even still, some areas won't have good coverage in digital maps, either. I've been some places like that, too. YOU have to be a bit more flexible to work with whatever resources are available. I think that device manufacturers packaging "trail maps" onto the devices is problematic because it sets up higher expectations for potential customers than they ought to have. I've been riding long enough that I distinctly remember the days of riding where the best expectation I might have for a trail map might be a vague handout at the trailhead printed by the land manager, or maybe a print guidebook that I'd have to purchase, with similar quality maps (along with written descriptions) where I'd have to photocopy pages of the route(s) I wanted to ride, and carry USGS topo quads so I could refer those maps to the landscape in general. And more often than not, there was no trail map, so I had to rely on my own senses, a lot of dead reckoning, a sense of adventure, and enough flexibility to deal with wrong turns.
4. As for bluetooth, I can't say I've ever had a positive experience with attempting to maintain a long term data connection over BT. Speakers work fine. Short term data connections work fine (I occasionally upload from my Edge 520 via BT and then turn everything off when it's done). This is especially true when phone signals are sketchy, which is incredibly common in a lot of places where I ride my mtb. Any sort of phone connectivity gets flaky when the cell signal drops out. If you want more reliable live tracking and communications when you're out riding your mtb, you probably ought to look at a satellite communicator type device.
5. As mentioned before, you WILL suffer from poorer quality GPS reception from such a cheap phone device. It's not something really addressed in phone specs, but the quality of the gps chipsets (and specifically important to gps signal quality, the GPS antenna) varies WILDLY among phones. Only some high quality phones have really good GPS accuracy with the GPS chipset alone. Almost all of them rely on augmentation of the GPS signal using cell tower triangulation. When you're out on mtb trails, farther from civilization, the quality of that cell tower triangulation wanes so the device's location services become more reliant on the GPS chipset and GPS antenna. And if those bits of hardware are cheap/lower quality, then you're going to get low quality locations on that device. It happens a LOT. I look at Strava flybys from time to time just to see what trail traffic was like when I was out riding, and where other people went. It often exposes me to other route possibilities that I hadn't considered. I see a LOT of really terrible quality GPS data, and almost invariably, Strava tells me that the track was recorded by "Strava Android" or "Strava iOS". I do see some quality tracks laid with those apps, too. In seeing that variation, it tells me that the difference comes from the hardware, and that some devices use good hardware, whereas others use token trash. Strava doesn't report what hardware people were using. It would be informative to see that, and be able to identify what devices have poor GPS hardware.
