I find the facility to be extremely useful however, we have experienced technical issues using the facility with EMIS Web which has been frustrating for the practice.
I also have to use my personal credit card to pay for the letters as the practice doesn't have a card to pay with (we don't use one enough to justify the cost). I did try to set up an account but gave in after a couple of attempts. Next time I use the facility, I will try again.