Has anybody tested the solar yet in the real world?

It's a bit early to say for me. I think it is useful?

I wish there was clearer information about how much battery is gained through solar. The Edge 1040 Solar tells you are every ride how much time you gained. The Enduro should do the same for each day.

This!! you have no idea how much you gained. Compared to the enduro 2 I have the feeling that it is easier to reach 50k lux

See 'THE SOLAR PANEL, AND BATTERY TESTING' in the article below:
https://www.dcrainmaker.com/2024/08/garmin-enduro-3-in-depth-review-vs-fenix8-solar.html

Before I returned mine, I had it sitting on the lawn chair in the backyard for just over 2 hours(I figured why not). This is AZ, full sun, middle of the day and it never moved/gained a percent. It didn't drop any either, but it didn't seem to charge in such a way that it added anything meaningful. If I remember correctly, it was at 68 or 67% and stayed there. I know when I brought it in, it was at whatever it started at.  

That’s disappointing. With this new improved 50 percent better solar I’d expect a percent or 2 from 2 hours in the full Sun. 

DC’s article is great but doesn’t really mention “I had it in the sun for X hours and it gained X percent” Hopefully won’t be long before a YouTuber does a proper solar charging test. 

I think the watch has a lot of potential, but I could not wrap my head around paying 972$ after taxes for a watch with so many little issues. I think software updates will fix most things, but I'm not paying a premium to test a watch for Garmin :-p 

I think you're correct, someone will put together a test video soon. I was really surprised that it didn't gain even a single percent. Just curious, what has your battery life been like? For me, it never drained less than about 7-8% a day without GPS. Usually about 8-9 % with two trips to the gym daily. That would have put it a bit below the published stats. 

I haven’t got one yet. The enduro is my pick of the releases but wanted to make sure the solar was actually much improved and actually did something before purchasing. It does literally nothing on my current 7X pro sapphire solar as many YouTubers have proved. The 7 to 8 percent drop as you describe is indeed below Garmins advertised figure and about what I get currently on my 7X Pro SS. Agree not good to be a beta tester at that price but that’s just life being an early adopter of a Garmin flagship. I had it with my 7X, it was literally 6 months before a stable release. 

Do they promise that it charges the watch in normal operation? Or does it just slow down battery consumption? Iirc it may charge in battery safer mode

The Enduro 3 page on Garmin's website doesn't actually state that solar alone will charge it up, however it does state the following in the product specs section:

Smartwatch Mode: Up to 36 days / 90 days with solar*
Battery Saver Watch Mode: Up to 92 days / unlimited with solar*

*Solar charging, assuming all-day wear with 3 hours per day outside in 50,000 lux conditions

To me, when i first read it the "unlimited with solar" part of that suggested that the watch might gain charge in battery saver mode, although in fairness it doesn't actually say that it does.

At the very worst I expect it to prevent it from losing any charge if it gets enough solar whilst in battery saver mode. That would mean that the battery level will never go down in that mode.