If your still wondering this one, this is a good comparison between the ICON and the M8 with WP...
HTC One M8 for Windows vs Nokia Lumia Icon (Video) | Pocketnow
Pretty much what everyone says, side by side, performance is ABOUT the same, both good phones but, the camera on the ICON blows away the M8, it's not a bad camera on the m8 but, for quality and detail, it's not even close..... again what is more important to you...
You can't really have it all with one Windows Phone device, can you ?
For those with an Icon, is the incentive there to upgrade to the M8 when the specs are pretty darn similar? There is no way I would extend my contract 2 years to upgrade from an Icon to an M8. Now if you wanted to buy outright then that's different but I can't help thinking that there will be new phones coming relatively soon that will leave both the Icon and the M8 in the dust.
Unless you really need a feature the M8 offers more than the camera, then no. Not a big reason.
If you have a ICON, like I do, I would wait till next year anyway, WP 9 is rumored and I will bet it will support features that the ICON does not support, if your going to upgrade, I would wait.
Personally, the only advantage I could see with the M8 over the ICON for me would be the MicroSD slot, as storage on my ICON is at a premium.
Not really worth spending $400-500 on for that one feature(I wont sign a contract, unlimited data)
Why would you take it j never really used it? I said right in my post I owned an Icon.
Just because you had a ICON, does not mean you lived with wireless charging for a while or even used it. Most people who complain about it, never used it or used it for a very short period.
We can agree to disagree here, I think it rocks but, again, I have had 3 phones with it.. and it's all I use besides in the car.