I think for now I will stick with my Lumia 950 XL. I've come to the Windows mobile OS a long time ago, with a HTC Touch Diamond running Windows Mobile 6.1. I never liked Android's UI or Apple's UI. For some reason, a grid of icons doesn't appeal me too much. And I think Apple devices price is big just because they have that particular logo on them.
Anyway, since Windows Mobile 6.1 I had a HTC Radar with Windows Phone 7.5 upgraded to 7.8, a Nokia Lumia 1020 and now a Lumia 950 XL. I have converted my wife too to Windows Phone. Her first Windows device was a Nokia Lumia 800. Then I upgraded her to Nokia Lumia 925 and now she uses a Lumia 950.
I must be honest and admit that Samsung Galaxy S8 appeals me with its display almost without bezel, and its Snapdragon CPU. What I like at SGS8 are its design and its hardware specs. If that device would have run Windows 10 Mobile I would have definitely bought it. I understand that it is possible to have Cortana as the personal assistant on SGS8, and it is possible to have the notifications received on your phone transferred to your PC running Windows 10. But for now I don't feel inclined to spend 800$ on this new device. I'll wait until June when my current Vodafone Romania contract expires and decide then.
If Microsoft, at Build 2007, gives us some hints about what its intentions with Windows 10 Mobile are, and gives us some plausible roadmap for a new device running Windows 10 Mobile (maybe it's Surface Phone, maybe it's something else) then I won't switch sides in June.
Otherwise, if I don't feel that Microsoft intends to continue to invest into Windows 10 Mobile development, and they continue to act like the integration of their cloud services into Android and IOS is more important than their own mobile OS, then probably I will invest in a new SGS8.
In regards of apps ecosystem, I'm probably one of the few people who is content with what Microsoft Store has right now as UWP apps. I mean, I have Facebook, Twitter, Kindle, Instagram, Flickr, WhatsApp, Skype. That's enough for me. Yes, I am frustrated from time to time when some local service provider has an app only for IOS and Android, but I can get over the frustration. Most likely I can use the provider's web site to do the same thing I would have done with the app.
By the way, the DeX doesn't interest me at all, as was it with Microsoft Continuum Dock. At home I have a laptop and no monitor, at work I use a laptop also. I don't plan on carrying around a mouse, a keyboard and some cables.
So, the short answer for me is not right now, but that might change depending on how Microsoft presents itself at Build 2017.