Psone Modchips ? For Australia

Could someone please tell me which mod chip is best to buy and who from, as I have checked the following sites and there all so called experts & all different in price.
modchip.com
psxonechip.com
shatami.com
psxtune.com
playstationmodchip.com
modchipsx.net
and a few in australia
I would like to buy one and test before I buy a handful and do some of my mates consoles.
I even read on one site as long as you have a boot disk you don't need a modchip ?