I've been using Microsoft's new browser, Edge, for some time. I've only been using the production version; I was not part of the "Insider" programs and those releases of Windows. What I'm seeing, you're seeing.
The UX in Edge is terrible. I'll get back to that in a minute.
What about the important things? I don't have the means to test a browser in full technical detail, so my opinion relies on reviews from sources I trust that say Edge is secure, compatible, and performs at a competitive level. I'm not sure I've noticed much difference between IE11 and Edge, but I'll trust others who say Edge is improved. Because Edge is based on contemporary code rather than the dated code of the Trident engine in IE, I think it's safe to say that Edge is more secure.
One thing coming in Edge, very soon if today's press reports are accurate, is Extensions. The ability to expand a browser in this way is a signature feature pioneered by Mozilla in Firefox and is a key feature in Google's Chrome. Microsoft is catching up in this regard.
But then, the UX...
The user experience in Edge is enormously disappointing, blunting what might have been a very sharp browser. Here's one example, from IE11:
Of course, this is the favorites bar. I use it for my most commonly visited sites as well as for sites or pages in which I have a particular current interest. Importantly, note that I have removed the captions and just display the icons, giving me quick, visual access to my, well, favorites.
Equally useful is the "system tray" in IE:
These icons provide quick access to the most commonly used configuration and control options in the browser. Note that I expose both the View Source and F12 Developers Tools icons because in my work I use them a lot. More on that in a second.
In Edge, it's not possible to display only icons, which destroys a very useful feature. I don't know why this is the case, although the settings available in Edge are incredibly sparse compared to the deep, rich set of IE11 options.
Here's a revealing comparison of Edge (left) and IE11 (right):
I don't use IE11 this way but I configured it to show tabs on their own row. That leaves four elements in the top matter of IE11: the heading bar, the address bar, tabs, and favorites/tray. As you can see, those four rows have a shorter combined height than the three elements shown for Edge. The black at the bottom on the right is the space not consumed by IE11. In my normal mode where the address bar and tabs are on the same row, the space savings is even greater.
Why the extra space? Two reasons, I think. The first is touch. On a smaller device, the IE11 icons in the favorites bar are small and difficult to touch accurately. I deal with such issues, when possible, by zooming with a stretch gesture. Nonetheless, I admit it's not a good UX situation. The second reason is flatland. Because the flat UI lacks visual clues about the delineation of objects on the surface, more room is needed to set them apart. Edge's icons are also larger to begin with, which is also true about Windows 8/10.
One missing feature I really don't understand is in the back and forward buttons. In IE11, holding down the mouse button over those buttons drops a list of recent history, allowing one to skip back/forward several pages rather than just one. This is not possible in Edge. Touch is probably the culprit here, although Microsoft could have taken a long touch as the signal to provide the list. I thought this feature in IE was incredibly useful and I really miss it in Edge.
Another example of the UX going haywire can be found in Developer Tools. I recently started using two displays and for convenience I moved the Developer Tools window to the secondary display. IE11 remembers this and on every subsequent invocation of the Tools, the window appears on the secondary display. Edge does not remember and opens Tools directly over the working page. While this is not something that will cause many people to complain, it illustrates that the removal of UX features from Edge is extensive.
Why Is Microsoft On This Path?
I can't say for sure. However, I got what might be a hint when I watched Microsoft's Connect(); // 2015 event this past November. Visual Studio is going multi-platform.
That makes sense. Microsoft is clearly building applications for more than Windows; it has built Office and other apps for iOS and Android.
Suppose Edge is Microsoft's multi-platform browser?
Windows has an incredibly rich user interface, honed over decades. But duplicating rich UI features across platforms is difficult. Thus building a UI that works across platforms becomes a lowest common denominator problem. I call the resulting UI "flatland" for its extraordinary lack of visual cues and I've railed against it before. It's terrible.
While I use Edge every day (I've let it be my Windows default), I also use IE11 every day, by choice. If Edge was a worthy replacement for IE, that would not be the case.
Microsoft has simply tossed away years of UX expertise and thus assured that Edge is a disappointment.