In my office before, we had computer chairs for most employees. We liked the mobility that the wheeled chairs give us. We don't need to stand up if we are just to reach out for something.
But computer chairs are quite expensive. And they are not really right for the waiting area of our office. So instead, we bought Cofta Monobloc Plastic Chairs. These are on the high end spectrum of plastic chairs in this part of the world. We the Ruby ones without armrests in order to save space. Besides, the guests do not really stay long in the office.
Cofta Monobloc Plastic Chairs are comfortable because the bend of the back rest is just enough to give the back some comfort. But since it is plastic, it is quite hard and therefore not for long term use. I use one right now, but I am also sitting on a cushion.
These are also very durable chairs that last a long time. As long as you don't toss them or kick them around the room, they can last for years. Anyway, one drawback though is that dirt sticks on the surface of the plastic. It seems that after some time, the plastic lamination of the chair comes off and the dust and other dirt stick to the surface and it is very hard to clean. We would end up scraping the surface to remove the dirt but this only exposes the inner part of the chair and thus it attracts more dirt the next time. Oh well, but that is a long process and with its price, it is still worth it.