Like a number of you here, I've jumped over to the LG V10 from my Lumia 1520.
The latest (at the time) build of W10M, 10586.11, let me down at a critical point during a holiday vacation a couple of weeks ago, and made the decision to switch pretty easy... I was taking some snapshots, and after only 3 consecutive pictures, the 1520 got stuck on "Saving...", making me miss some great moments. Killing the camera app using the switcher didn't solve the problem, and a full restart was necessary, making me miss more photo opportunities. That same evening, I rolled the 1520 back to WP8.1 using the Device Recovery Tool, and spent the better part of 2 hours reloading updates and app installs. Rolling back to 8.1 means I lose the slo-mo video option, the updated Outlook client, and the expanded Notification Center shortcuts - all things that I really enjoyed.
Although I still love the WP interface (live tiles and such), I've finally gotten fed up with the lack of key features - no mobile payments, no support from my bank, and (...groan...) the app-gap. Also, with no official date on the release of W10M for the 1520 and the camera app issues, I've had enough. I paid off the small remaining balance on my AT&T Next plan and went shopping.
The LG V10 is nearly perfect for me... the camera (and camera software) is better than the 1520, and LG's current Optimus skin is insanely customizable. It's great to be able to use Android Pay, and having mobile banking support is a welcome relief. The buttons on the back make the phone so much easier to use, given its size, and the fingerprint reader is a very capable PIN replacement. Best yet, I'm still able to stay in the Microsoft ecosystem, with Outlook and Office, OneDrive, and great support for my Band 2.
I've still got my Lumia 925 that I'll use for playing around with W10M, but I'm much happier with the V10 as my daily phone.