I bought one of the chairs off ebay on the basis that they look like an aeron copy and have everything i need. should arrive in a few days and i'll let you know what they're like.
well, the aeron chair back is kind of high and a little more flexible so you can rest your head back if you want. to be honest, the head rest isn't really a big issue but the lower back support on an aeron is class and that ebay chair has the same mechanism so here's hoping!!