Sqeezy,
This subject was discussed on the forum just recently, try looking for it using the search facility on the top right hand side of the page.
Personally I wouldn't waste my money and prefer to wait for my a1c result from my annual check-up. In the meantime I use the 7,14,30 and 90 day averages on my meter to determine my average blood glucose control, I find overall it is pretty much in range with my hba1c, so guess its a good indicator.
Nigel