Safari Technology Preview? No, I hope no one uses that as their main browser. 😉 Safari, maybe. Personally, I think Safari is fine, but I prefer Firefox (whose marketshare appears to have fallen in the last few years) from both a philosophical standpoint and for the fact that I have bookmarks synced across different computers (and OSes) with it. God knows I don't use it for the snappy performance. I assume I'm in the minority on the Mac for this preference. 🙂
If you believe most browser statistics, yes--about half of all Web traffic comes from Chrome, though probably a bit less on the Mac (haven't looked it it broken down by OS myself).
I do use it as my main browser, and I have done so for many months.
I have a reasonably modern and well-equipped 15" MacBook Pro. Quad-core processor, 16gb of ram, and a speedy SSD drive. All that and I still had (and still have at times) resource problems with Chrome over time. I do keep a lot of tabs open, and by over time I mean from a few days to a few weeks. Inevitably, I have to hard kill/restart chrome. I have similar problems on a modern Ubuntu-based workstation. That said, "in a vacuum", I think I prefer the "look and UI" functionality of Chrome amongst all the modern browsers. It is just that Safari has and continues to run the best over time* on my MacBook Pro (Sierra and the previous two main OS versions). Because I use a lot of tabs, I was unwilling to use the mainline Safari 9.x, and so turned to using the Technology Previews. I added a few extensions, and have a fairly stable experience. With the release of Safari 10.x, I supposed I could have moved to the mainline release. But I have not seen the need yet, and I actually like the more frequent release patterns for browsers that Firefox and Chrome and now Edge and Safari (Technology Previews) have embarked on. Some bugs do seem to get fixed faster.
* By best over time I mean lowest cpu and memory utilization over time, with fewer crashes.
I should say that I have not recently given Firefox a lot of use on my MacBook Pro. It used to be my main browser everywhere, but I was finding a few years ago that Chrome outperformed it quite handily. So I switched to Chrome pretty much everywhere except iOS, and just lived with having to restart every so often (which is admittedly easier with the right extensions installed). But the use of Safari Technology Preview has eliminated even the need for that on my MacBook Pro . . . at least until new revisions are released every month or so.
More people should try it as their main browser. I think they would like it, mostly, and appreciate its performance on its native system; though again I do still like the "look and UI" in Chrome a bit more still.