... my 40 hours on the 530 comes from what some people would consider extreme "battery saving" so zero backlight for daytime use, no phone connection, and a few of the other recommended settings, I note that "battery save" mode still uses 30% backlight / always on which seems excessive to me. I find the zero backlit screen level perfectly adequate, clear, readable. My decision re Explore 2 will be mostly based on whether it can also provide the same visibility with no backlight, interested in your view of this.
I think in battery saving mode you'd still have easy access to turn the backlight down to zero. The Explorer 2 native un-backlit screen brightness and contrast is exactly the same as my Etrex 30x - but the screen area is very nearly double and that, along with much improved font rendering, makes a big difference to general legibility. That is just comparing those two models - I don't know the 530 but I imagine the Explore 2 is similar. On my Etrex 30 I do need some backlight in most daylight conditions - I use about 50% and a 30-second timeout. Yesterday taking the Ex2 out in overcast conditions (best, I find, for an unlit screen) it was indeed very usable without backlight - though still better 'company' with a lit screen.
Thank you all for the very interesting comments so far.
I think it is already clear to me that one device is not practical and I should get the best option (hopefully) for each sport
Compared with the Etrex, the Explore is NOT a good hand-held or walker's device. It seems over-sensitive to any erratic movements (such as dangling from a lanyard) and, as I mentioned elsewhere, the track-up map is not steady at slow walking speeds, although fine at cycling speeds.
Was the version you bought with the charging baseplate or are you testing without to get used to the operation and battery life.
I am happy to either use a dyno hub run through a sinewave or similar or just a battery pack.
Do you think the charging base is a decent and hopefully reliable addition ?
And regarding your comment regarding using as a standalone and not pairing to a phone or Garmin Connect is this for testing
purposes or do you think it is better / more reliable in operation as a standalone device ?
I'm no longer interested in anything longer than a 10-hour day - on tour say - and don't expect to take it anywhere where I can't recharge it overnight - so I'm not really exploring the runtime limits as you might wish. The external power base looks very overpriced to me, but I suppose if you have a regular need for extended runtime then it's an option. It's poor from Garmin that the basic unit doesn't have the power contacts in the mount - meaning its not upgradeable/retrofittable. If you only have very occasional need - 1x 600km per year and PBP maybe - then I would think powering it externally in the usual way would suffice.
But I would argue quite strongly that for a mission-critical ride such as PBP I would not want to be reliant on rechargable anything - neither lights nor GPS. I would still say the Etrex is a better tool for that job, you can buy new AAs anywhere along the route and you'd only need to do that once.
Standalone - I'm quite impressed with how well this works - for our purposes this is how we will be using it, in a dumb 'track overlayed on map' mode. General setup is no more difficult than it is on the Etrex. The only drawback (and it is a serious one) is the need to physically connect via USB to add new Tracks and remove recorded Tracklogs. Constant USB disconnection is I fear a sure resipe for bricking the device sooner or later. (x-post with LateStarter above)