I like it because it's the fastest browser. It's lights on CPU and RAM, and also best on battery life. It doesn't siphon my data off and send it all to Google so Google can sell it to advertisers. Edge has adblock and ghostery to supplement a more in-depth solution (PIhole, or hosts file), what more do you need?
Siphoning data off to Google would be bad, right? MS siphoning it is OK though?
TBH I've never really looked into adopting Edge personally because Win10 has never been my primary OS, but a personal showstopper right off the bat would be Edge's lack of cookie management options, they went slightly further than "COOKIES: Y/N" and then slumped in their chairs and said "meh". I have Firefox configured to allow all cookies until the end of the session plus it has an exceptions list, plus I can delete specific cookies on a per-site basis if I wanted to.
One consistent problem I have with Edge is fixing it when it's broken for customers. Its user profile folder is a complete mess: finding folders like a 'MicrosoftEdge' folder inside Microsoft Edge's "Microsoft.MicrosoftEdge_8wekyb3d8bbwe" (WTF) folder is always a "delight", there are several folders in various subfolder structures that could contain a browser cache or the cookies or whatever. I often find that filesystem access has been denied to the folder and I have to fight the OS for it, or that write access to the folder has been denied "because a program is accessing it" despite the fact that Edge isn't shown as running in the process list and that the only way to fix it often is to go into Settings and press its reset button, or that reinstalling Edge through mile-long PowerShell commands is one of the few solutions I've ever come across.
In stark contrast, I encountered a rare problem with Firefox on my tablet recently: it wouldn't load any sites after its local home page. I narrowed the problem down to ublock origin, reinstalling the add-on and reinstating its default settings didn't help so I went into the FF profile folder and deleted ubo's extension data folder. Problem solved, no meaningful data loss needed.
For me another fairly serious annoyance is MS's tendency to overwrite user preferences with Windows Updates, Edge included. Furthermore, instead of going with the minimalist default home page that most browser makers have finally seen the light and decided that it was for the best, MS decided to go for their convoluted semi-offline MSN design and then reinstate it periodically when - heaven forbid - users don't want it.
On the topic of performance, I can't say I find your argument altogether very convincing:
https://venturebeat.com/2018/07/09/browser-benchmark-battle-july-2018-chrome-vs-firefox-vs-edge/
A dig through the benchmark results doesn't really suggest a clear winner to me; on one hand Chrome 'won' the most benchmarks by not very much, also a fair few benchmarks gave close results, and sometimes one browser appeared to spank the others quite decisively. In my own experience a particular platform may handle one browser better than others (without having a particular merit or drawback such as lots/lack of RAM/CPU); in the past I've even found IE to perform better than alternatives on a given platform, so coming out and saying "x is the fastest browser", IMO, is a bit silly.