For me as a beginner this balance board is perfectly adequate. I am very satisfied with the price / performance ratio. The board consists of hard plastic and with me flexes nothing. Large enough, it is also. It has not slipped myself on parquet and tiles and the foot of the unit has harmed and no soil.
I will continue to practice a little and hope that allows the knee problem solve. But I've seen during the training also noticed that almost all of the body has to do something. So a good, effective and space saving exercise equipment.
Addendum 03.05.2014: I had a voucher for the online shop and there were problems when cashing on the homepage. I wrote an email to the seller, describing the problem that was solved very fast and very friendly. I call that a perfect customer service.
