The guy that finished my flat work put a really smooth finish on it. My goal at the time was to put an epoxy coating on it so I did NOT seal the concrete after.
Fast forward a couple of months and the guys that did my spray in foam insulation job were less than careful with their drop cloth placement and in several places coated the floor with foam. If you have ever seen that stuff, once it sticks, it is stuck on...FOREVER... I was so sickened by the overspray, I gave up on the dream of an epoxy coating on the floor and have been living with just the concrete ever since.
It's
okay... Not smooth enough to be slick, but smooth enough to sweep up pretty easily. It's got some oil stains in it in places, they seem to show up more when it's humid.
I've seen enough horror stories from guys with the nice epoxy floors that have it coming up if they drive on it with hot tires or leave their cars sitting on them for too long that I'm now glad I didn't go that route. I'm sure some of the commercial type epoxy floors are better...but they are

compared to the home remedy types.