Yes and no.  It depends on where you are from.
It is much cheaper to buy these things at home or in Hong Kong, as the stores in Shenzhen are very very pricy.
Brand names back west sell for double here, and also the sizing for shoes and clothes are based on local sizes which are quite small.
I would suggest you bring most of what you need unless you have an unlimited budget, as anything reasonably priced will be crappy quality.