Just from my experience with w10m (Lumia 930):
In short, if you need your phone for work related stuff and you need ir to be reliable, just don't. Stay with 8.1, at this point, it is far superior, more fluid, fast, stable and reliable. Sure, some w10m features are nice and the design is a nice change but other rhan that, it's not worth it at this point, at least for me.
It created so many problems for me. My phone is laggy and slow, huge battery drain and overall it just feels like I am using a cheap Android device, not a former flagship. Constant wi-fi problems and need to manually turn wi-fi off and on again. I can't download keyboard predictions now because of some bug. No e-mail sound notifications. For some reason, some apps in the store are in different languages (mostly arabic or spannish). That is just to name a few.
Other things I dislike:
Edge - no swipe gestures or forward button (wtf???)
Mail - just horrible formatting when reading e-mails. Writting is even worse, slow and unresponsive and just pain to do.
Circular design of the People live tile (lol)
Hamburger menus (sigh)
I do realize that this is just and insider build (.36) and I really hopw it gets better as other thatn the things I mwntioned I like the system. It's just ... Yesterday I just got the feeling of using a cheap Android phone and not the awesome, fast and reliablw system I was used to and which I was proud of and would recommend to anybody. Now I just don't know, I really feel sorry for the people who bought the 950 & 950 xl with system at this state, it's so far from finished ... And yes ... I have done a "hard reset". Which is another thing I have a problem with. When on 8.1 I have never even heard about needing to do something like tha. How many people do develop the w10m? 5 people? Will we really be forced to "jump ships" in the future? There are so many people leaving the platform already. I am sad...