I am using it on my 925 since Saturday. In comparison to the last preview build I installed (10240, I guess - don't remember anymore) it's pretty stable, and all apps are working.
Some glitches here and there, but nothing that compromises. The speed is good, but not so fast like on 8.1. The only bug until now is that I cannot change the 4 main toggles in the Action Center, it crashes. And the battery life is much worse than on 8.1, it drains much faster. Notice that I haven't hard resetted the phone.
If you are willing to test it, it may be the time, if you do not depend on some specific apps that may not work properly. But be prepared to roll back (always), if something goes out of plan!
So is it stable enough to use on my only daily device?
So is it stable enough to use on my only daily device?
I'd suggest you wait for the next build, coming soon. If you only have the 925 as a daily driver and you've been waiting this long to play with it, you better not risk anything. The builds so far have needed a hard reset to pick up fluidity and drop any bugs due to corrupted upgrades.
I'm using it on my daily driver, but I don't use the phone for work or something like that. Also, I'm willing to roll it back as soon as I notice it's not attending my needs. If you are not willing to risk hours reinstalling everything, or you need your phone working flawlessly, I'd recommend to wait for the next build, like Nicholas said, and install it after a couple of days and after reading some reviews from people who installed it (even though I don't see a lot of 925 owners here ). It's like on PC, the last Insider build was released on Slow Ring and some driver update broke my Internet connection (wifi and Ethernet), so I had to roll back to 10547 - so it's not guaranteed it's going to work better, although it should.
But if you want to play and have time and patience to do so, I'd say it's a nice build, from my experience and from what I read around here.
Working fine for me in daily use and IME battery life is better than 10536, although still not as good as 8.1.
Issues I've found are can't change the quick action buttons (noted above), can't set a 2nd mailbox as a quick status option on the lock screen, MSN Weather still doesn't work with the lock screen (using AccuWeather which does). Haven't tested bluetooth SMS reader yet, which wasn't working before.