The slab in my garage was poured with fibermesh,and it cracked like a busted windshield in a matter of weeks,but I was not surprised or upset-numerous masons had told be "cement was born to crack",and the best you can do is to install control joints so it'll crack "where you want it to" rather than randomly..
However the contractor who did my floor did not put any control joints in,and said re-bar or mesh was not really needed for what the slab was going to be used for,but if I wanted it,I could pay the extra 600 bucks for it..he said the fibermesh is as strong or stronger than steel reinforced,and adding metal may even weaken the slab rather than help--and if I wanted a car lift put in later on,the re-bar or mesh could present a problem with its mounting..
I didn't go for the metal reinforcement,but sometimes wish I had..despite the numerous cracks there is only a few that open up a bit more during winter,then settle back down after the frost leaves--they laid a good 6+" of crushed stone under the slab,they poured it from a cement mixer trucks like concrete,and the resulting "flood" of water inside the foundation walls took a day or so to seep into the dirt underneath..he said that helps compact the gravel,and they did use a "whacker" tamper to tamp the stone before doing the concrete pour..
They also came back the next day and sprayed some kind of sealer on top of the slab with a garden sprayer type thing,I think it may have been linseed oil..it did seem to repel oil spills at first,but after a few years oil would sink in and stain it--my vehicles leaked oil and ATF,and a little gear oil,my diesel truck lost a lot out of the oil pan,and I had to top it off fequently,it got to the point I was putting flattened cardboard boxes under the engine in hopes of keeping the oil off the slab,and I'd burn it in my wood stove after it was saturated..
Despite the slab getting "oiled" in one area often,to my surprise it came clean fairly easy using blue Dawn dishwashing liquid and a sponge mop,then hosing it off--it is still stained there some,but it seems the oil left down deep does help repel any future spills from just "sinking in"..
I saw an ad on my Facebook feed the other day for some new Rustoleum "Mettalic Floor Treatment" for concrete..makes it look like polished steel,and supposedly protects it from oil,gas,atomic bombs,etc..
I could have painted my floor after it was poured,but after seeing what they looked like in local warehouses and commercial garages that used it,I passed--hot tires would leave tread patterns or peel some paint off,and in heavt traffic areas it would wear off where forklifts and carts were used...the stench from that epoxy takes a long time to dissapate too..
My friends shop had the floor painted,after that you may as well have been on roller skates working under the lift--spill a bit of oil or anti-freeze and water and its worse than ice with greasy soled work shoes on...he got so sick of slipping and getting wounded that he used some house latex paint with sand mixed in it to regain traction..nothing worse than trying to wrestle a transmission back in while your feet are slipping like your on ice !..