They are ok in quality, the originals were only ok too; I used to have several broken ones that I saved for parts, the metal seemed cheap. From what I have read, early Cuda handles were slightly convex and the Challengers were slightly concave. The replacements, even from Mopar, are kind of in between so they could be used for both.
The repros are equal or better than the originals. Driver side handles have broken regularly since the cars were new. There were different door handle contours on the 70-71 but were combined to one style for cost reasons. The Challenger are different as stated in the above post. The outer side is curved to match the door skin contour. They are generally about $50-$ 75 average each. Don't pay much more as there are only about 2 different manufacturers of these regardless of who sells them. If you are going to use the car as a daily driver, pick up an extra driver handle.