I have one and it serves me fine, I use it for recording where I ride and then saving the data to the Bryton website.
The maps are fine but the screen is quite small and I don’t use them for navigation, I like maps – the battery doesn’t run out and they don’t lose satellite signals!
The battery life is good for a long days ride and it does well keeping a signal. All in very good.
I have a Bryton HRM strap going spare if you decide to get one.
Downside – I broke the screen on one and they are irrepairable. However Bryton did offer me a replacement at cost which they didn’t have to do.
So, if you want recording where you went they are fine; the maps are good but the screen too small for me so using them to navigate by is a personal choice.
Having said that I’d be happy to swap mine for a new 20; it does all I need but they weren’t out when I got my 50.
Chris