I've been using the 530 on a 4 1/2 month bike trip through South America. We still have over a month to go. For each day we have a GPX file that I load and follow the route. The maps work really well - I love how you can just extract whatever maps you need from OpenStreetMaps and put onto the 530. We have 109 riding days on this trip.
Issues I've found:
1) The Navigation features sometimes freeze and stop working for a while. Typically after riding 100km or so, then it recovers after maybe 5-15km more. Doesn't happen every day. It happened out in the middle of the Salar de Uyuni so definitely not a problem with satellite reception! It is imperative to have a backup device because of this failure. OsmAnd phone app with tracks loaded works great, or Maps.me.
2) It doesn't understand switchbacks. It keeps calling them U-turns which is confusing. Come on that should not be so hard to fix.
3) It should be easier to load routes without a computer. Most people on this trip have only a phone and it is so clunky that they all just come to me so I can use my laptop to load maps or routes for them. You have to improve this process. Most people REALLY don't have a computer on trips any more. Computers must be supported and are ok for home, but it HAS to work away from home too.
Ending on a positive note: Battery life is exceptional! Best of any device like this I've used or heard of. The other day I did a 160km stage and my battery was at 82% after. Killed it!