We just use it on a Zire 21 which you can pick up off ebay for around £20, though one of the teams prefers print outs.
The beauty with having in on the PDA is that you have all the rounds for the next 7 days or longer on there so if you are unable to work one round for whatever reason you can simply go to another area without having to go back to get different printoffs.
It is also good when I'm on holiday, as they can simply carry on through the week working with the PDA, then I download it all when I get back. Simples