Okay after a bit more reading (the wiki was good) here is a good roundup
Pet microchip companies square off in a scientific "scan-off" - Wellsphere
and here is at least one price reference on the recommended universal reader.
HomeAgain Universal Worldscan Microchip Reader - Home Again - PetSupplies4Less.com
At $350, it's not on my current shopping list, even a $65 daily rental (
Pet Travel Store: HomeAgain Pet Microchip Scanner Rental ) can go to h###.