Gary,
I have a 40x60 barn with the fiber floor and no rebar. It was extremely hot the week we poured it and we had trouble keeping it from drying too fast. None the less, the crew completed most of it with a finish that is almost mirror smooth. There are some areas in the corners and around plumbing that could not be reached with the power trawler and show fibers sticking through, but even in a basement that was not going to be painted it would be ok. I have two areas that cracked, both where the sun was beating in through the overhead door openings, but they are not so severe that they are noticeable if you aren't looking.