Polished concrete floors, when done properly, can be wonderful.
They really have lots of advantages, for example, they can:
1.be beautiful, through finding the right mix, aggregate, depth of polish, etc,
2.be cost effective, as often a concrete screed maybe required for the floor build-up anyway,
3.be thermally efficient, through direct contact with the source of underfloor heating,
4.offer variety in colour, with huge choice available of sands, aggregates, additives, etc
5.hygenic, through their sealed nature and lack of joints to trap dirt
6.durable, though their solid hardwearing nature
On the other hand, a badly done concrete floor can look messy, unfinished and can be a disaster.