Techniks collets are made in Taiwan and are considered to be very high quality collets. Typical run out for a Techniks collet is 0.0002". I've tested them against Lyndex, ETM and Rego-Fix and with the equipment I have available, they are as good as the other high end collets but at a lower cost. They are also at least twice as accurate as the typical Chinese collet. I use mostly Techniks collets on the mill and save the Chinese ones for the lathe.
The nut has a lot to do with the accuracy of an ER collet, Mark, as does proper torque on that nut. ETM, Rego-Fix and Techniks all make good nuts.