Looks
Visually, the two browsers are very similar. In the screenshot below, Google Chrome is on the left, and Microsoft Edge is on the right. As you can see, the window chromes - the title bars, address bars, etc. - are not very different between the two.
The situation is similar when you click the menu button in the top-right corner of each browser. Microsoft has altered Edge's menu so that it is not exactly reminiscent of either Google Chrome or the old Edge browser, but combines the styles and functionality of the two.
The biggest visual distinction from Chrome that I've seen in my very brief trial of the new Edge is in the settings page. Edge's settings page hardly resembles Chrome's; in fact, it reminds me much more of Firefox's settings page.
The big functionality difference here is that Google Chrome allows you to sign in with a Google account, while Edge allows you to sign in with a Microsoft account. Once you get past the visual differences, though, both settings pages actually work pretty much the same - for example, the "Site Permissions" portion of both offer the same choices of plugins or parts of pages that can be enabled or disabled, and the "About" portion of each shows the version number and automatically tries to install available updates when opened.
Extensions
As you may be able to see in the screenshots above, I have already installed uBlock Origin into the new Edge browser. The interesting and exciting thing is that I did so from the Chrome app store.
Microsoft provides an extension store for Edge, which in the past would've been the only way to get them. Now, on the new Edge's Extensions page, there is a button in the bottom corner labelled "Allow extensions from other stores." The "Learn More" link gives instructions on how to enable this setting, and how to go to the Chrome Web Store to install extensions. These extensions ask for exactly the same permissions, etc., as in Chrome (of course), and otherwise work identically in both browsers.
Performance
As expected due to the fact that both browsers use the Chromium engine, their scores on the Basemark Web 3.0 test are basically the same: 344.67 for Google Chrome, 354.78 for the new Edge browser. The score breakdown shows that the two are close enough that the point difference doesn't really mean anything, and practically, they (and most web browsers) work well enough that you won't really notice any differences anyway.
Summary
Google Chrome and the new Microsoft Edge web browser, at first impressions, are the same thing. What works in Chrome should work in new Edge, and vice versa - pages will render the same, they will be about as fast as each other, and extensions from Chrome will work in Edge (and, presumably, vice versa with new Edge extensions.)
I'm not sure how I feel about this. On the one hand, as an IT person, it would be great if a clean install of Windows gave me a usable web browser, which will now be available with the new Edge. It's also great that I can use the same extensions in both browsers, and that webpages should look and work the same in both. Microsoft Edge, as hard as it is to believe, is now a good browser.
On the other hand, I don't know if it's good for the web - which is supposed to be a decentralized, diverse system - to lose out on one if its major rendering engines (Edge's EdgeHTML engine is/was a fork of Internet Explorer's Trident.) We all remember the bad old days when it was IE6 or nothing, and webpages employed a lot of not-exactly-standards-compliant techniques to make themselves look and feel right, which caused issues when Firefox and other new browsers came on the scene. Will we see a return to that world when every browser, or at least most, are really just copies of Chrome? Sure, Chromium is open-source, but if everyone uses the same open-source base, the biggest contributors essentially decide the direction of the web. I just hope that Google and its contributors stick to the motto of "don't be evil."