I present to you, my decidely well-worn and weather beaten Bryton Rider 50 GPS cycling computer:
Background:
The Rider 50 was Bryton's flagship model when the brand launched to the market in 2011. Although still listed on the Bryton Sport website, it's no longer listed on that of Oceania Bicycles, Bryton's Australian distributor, which suggests it's probably now a discontinued model. I purchased this unit in October 2011 (my ride data collection dates its first use to the 30th of that month); it was actually a unit that had been returned to Oceania for a warranty claim; it had supposedly been getting water inside, but neither the Oceania service rep who assessed the unit, nor I in the subsequent five years ever saw any trace of moisture, even with the missing buttons apparent in the above photo!
Features:
At the time of its release, the 50 was pitched squarely at the then-current Garmin Edge 705, virtually identical dimensionally and loaded with the same data features. Although similar in length and width to current high-spec GPS units, its 21mm depth is comparitively brick-like against its slimmer successors.
The 50 has four default screens; three data grids, each customisable with up to six data fields (from a total of 44 possible selections) and a zoomable map screen, which includes many MTB trails. Handy. In addition to these default screens, selecting from the multiple workout programs can activate up to another three screens. Sensor signalling is ANT+, so the unit can be paired with any ANT+ sensors, not just Bryton models. My unit included a heart rate strap and a speed/cadence sensor, switchable between either function, but cannot perform both at once.
In The Field:
Initial setup was a bit time consuming, not the least formatting the data screens to work out which bits of info & wanted, and on which screens.
I set the supplied speed/cadence sensor to cadence, and left the speed sensing solely to the GPS. On that front it has mostly been very good. I ran it alongside an old-school wired wheel-based Cateye bike computer on several occasions in a range of conditions, and it's been close enough in its readings to be considered very reliable. That said, it's not perfect. Like all GPS units, it can suffer signal drift. This typically manifests itself when I'm in lap recording mode for training or an event, and if there's another sector of track close to the programmed trip point, it will trip the lap when it's not supposed to. This tends to be more likely to happen if I rush through the lap point setting process and don't stop for a bit to let it fix its position. It's only really suffered significant signal dropouts in heavy cloud & rain, under dense tree cover; this seems to be the only combination of environmental factors that upsets it - even with the missing button covers, it doesn't seem too phased by rain, it just keeps tracking. 
The monochrome screen can be a little hard to see at times; without backlighting it's not very bright and tends to get washed out with reflections on the screen. Low-level backlighting will help, but cuts into battery life.
The barometric altimeter is laughably inaccurate, however the Bryrton is not alone here; virtually all products of this type use this type of altitude calculator. Because atmospheric pressure is constantly variable, especially locally due to changes in temperature, the unit gets fooled into thinking your altitude is changing a lot more than it really is. Processing the ride data, possibly via map overlay trickery, cuts a considerable chunk of the elevation gain/loss off the raw data, probably to a more realistic level.
The build quality of the housing is very robust; my unit has been dropped, bounced, crashed on and ridden in all manner of conditions. However its weak point is the buttons. Integrated in a soft silicon rubber band bonded around the edge of the housing, the buttons tend to split and fall out after a few years of hard use; over the past year or so I've had three out of the four side buttons fall out. Although I've managed to retrieve them (they at least tend to push into the unit and stay there, to be picked out later) and glue them back in with flexible silicon, two have since fallen out and got lost, so I need a convenient key or stick to press the buttons - I get some weird looks in trailhead carparks "starting" my GPS with a car key!
Sadly though, My beloved 50 is dying a slow death. Although its recording functionality is all still going strong despite the lost buttons and compromised waterproofing, its battery is wearing out. When new it had a claimed battery runtime of some 15 hours, but now it's running out of gas at five or six hours. This is compounded by a dodgy connection in the USB port, which makes it quite difficult to get a reliable charge, so I'm never quite sure if it's going to have enough to get me through a ride. This also makes it flaky getting the ride data out of the unit and into the Bryton Bridge processing software for uploading to the Bryton website (I don't do Strava, I just load my stuff onto Bryton Sport). All things considered, five years is not a bad innings for consumer electronics, in this age of rampant disposal and deliberate obsolescence.
Summary:
The Good:
Almost bombproof build quality and resulting weatherproofness
Good accuracy of speed & distance tracking, even in tight terrain
Pairs to any ANT+ sensors, including power
The Not-So-Good:
Dim screen display without backlighting on; needs a low level of lighting to be visible, which cuts battery life
Flimsy button covers
Altitude calibration
Some features take a bit of navigating to.
Slide-on mounting is not the most secure. The retaining clip sits in quite shallow pits in the back of the unit, and once worn easily slip out. Additionally the clip tab on the bracket is prone to breaking off, and the rubber grip pads wear down.