The polystyrene hive has many benefits over a wooden version. It is lighter, cheaper and the insulation properties of poly mean the bees can overwinter better and have a quicker Spring start. No assembly needed, just a splash of masonry paint on the outside is needed (and you can go wild with the colours too).
Dont think of poly as the cheap alternative however. This is not polystyrene that you would find around a new TV, this is high density - 4 times the density, meaning you get a strong, robust hive that will last 30+ years. All of our poly national and poly nucs are UK made too - no importing.