I bought the metric set of collets from PM. They are decent and work, but not as nicely finished as an inch sized Lyndex collet I bought. I need to machine anything I am doing on nominal or lower since I found they only have about 0.001” on the plus side before it gets tight. The Lyndex collet on the other hand has at least a few thousanths on the upper side. I don’t have gage pins, so can test it, just estimating using a 0.375” rod.
Most of what I do is metric, so I am buying the inch sized collets as I need them. I can’t comment on if the inch sets are the same, but for the price, it is hard to beat. I figured I would start with this set so I had everything I needed and replace the most used sizes with a quality brand as needed, but not sure that will be necessary. A quality brand like Lyndex is going to run you several times the PM price. In case you are not aware, Lyndex collets are made in India, so even at that price you are not getting American made.