I will install the Win10 preview on my Icon after VZW/MS releases the Denim update (which if rumor is to be believed is just around the corner).
I will upgrade my tablet, my laptop, my wife's tablet and her laptop, and our children's tablet all to Win10 so that I am on one OS on all devices. Wish my employer would upgrade. I am looking forward also to the touch version of MS Office. I believe that MS is headed in the right direction with this move. I don't put stock in those naysayers who say that there are not enough apps for windows. How many versions of apps with the same basic functionality does one user really need. While there are some apps I would like to see, like one from my banking institutions, that is not a deal breaker. There are Windows apps or equivalents for pretty much every other major app on iOS and Android.
The current OS functionality in Win 8.1, how seemless it works between my devices now is great, I look forward to it being enhanced and improved in Win10.
You'd be very brave to take that chance on a phone without up to date firmware. The Icon does not fit that description and it's as likely as not to remain that way.
Ya, I signed up for developers preview immediately and never regretted getting WP 8.x updates from Microsoft. I'm running the Tech Preview of Windows 10 on one of my Desktops and like the changes. I'll be interested to see what it does for Windows Phone. I've really enjoyed having 8.1 on my Desktop, Surface, and Phone - look forward to doing the same with Win 10.
I went to developer preview for 8.1 after a summer of waiting for Verizon to release the official version with cyan. Been great, with only a couple of nagging things that would be fixed by updated firmware. Now, denim and Verizon can't test and release that, either.
So, Microsoft has been able to develop and release TWO firmware updates and TWO operating systems and Verizon won't succeed in getting even the firmware and the old operating system released in that time. That's embarrassing. And, Verizon apparently has no schedule for releasing them? I think the government could even beat that performance.