Firstly, the build quality is superb. Unlike cheap mass market chairs, where the arm-rest and/or back support rattle or move as you move them, the joints on an Aeron are a snug fit and you won't find any loose moving parts or sharp/rough edges on chair at all. The rollers are made of good quality plastic that rolls evenly and smoothly. Most importantly, it won't damage your wooden (or any other types for that matter) flooring. The graphite (or titanium depending on model) frame and the pellicle mesh make the chair extremely durable so much so that they are even confident enough to give a whopping twelve years warranty.
Other than build quality, the best known aspect of this chair is actually the comfort. The seat and the back are made of a strong pellicle suspension system which conforms to each person's shape thus distributing the weight evenly and avoid strong pressure over your body. The mesh design also provides the much needed ventilation, leaving your bottom and back cool and dry even after many hours of working/typing/gaming/(whatever that is you do in your chair), especially in a non-air-conditioned room.
You probably won't be able to appreciate the comfort of the chair just by trying it out at a showroom. You really need to use it in your environment to feel the difference. I have it for a couple of months now and not once had I felt any soreness or discomfort in my back and bottom even after long hours. Overall, I will say that the S$2k is money well spent.