If the concrete is poured well, it could be a nice modern industrial looking feature, suitable for a loft.
However, builders have found it a cost savings and try to market it as a trendy or loft-like feature.
I have seen some condos or so-called lofts where there's exposed concrete everywhere, which makes the place look dark, gray and bunker-like.
Also the the concrete forms must be done very well to have a clean smooth surface with very little pot marks. The Westside Gallery Lofts by Plazacorp is an excellent example of poorly done interior concrete work -- very rough with lots of potmarks and holes, even in the floors.
Some builders use plywood forms which creates a nice woodgrain texture on the surface. I've seen this done at Parc Lofts and it looks pretty good.
When floors are exposed concrete it should be either polished or acid stained and sealed to have a proper surface. Polishing is an expensive and labour intensive process as it involves grinding and polishing the surface with diamond pad equipped equipment. The result is a perfectly smooth finish like stone.
Acid staining is good way of colouring the concrete as it is a chemical reaction that penetrates the concrete which creates a durable finish that brings out subtle variations and veining like stone, and great for those who don't like the concrete gray colour.
Concrete floors are also an excellent base for a poured epoxy floor. Epoxy floors looks really slick and modern and it is also extremely durable. It also has a nice warmer feeling when you walk on it. I have seen a modern loft which everything inside was white and had a glossy white epoxy floor and it looks really sharp. It's definitely not everyone's taste, but I really like it.
Any exposed concrete surface should thoroughly cleaned and sealed, if not the concrete will dust off constantly no matter how much you vacuum or wash it. That happened to my last loft which was a nuisance. It's also not good for those who have asthma or other respitory conditions.
Developers will often include in the sales documents a disclaimer mentioning that holes, potmarks, colour variations and other blemishes are normal and perfectly acceptable for exposed concrete.
I have moved on from the exposed concrete trend, unless I have come across a really cool hard loft space. Nothing beats a smooth finish plaster ceiling.