UNC and BSW have the same thread per inch value, accept for the 1/2" size. Theoretical it would be possible to interchange them as they have the same amount of threads per inch. However due to the difference in thread angle, the connection would not be as strong as when using the proper combinations.
For the sake of pulling if you go with the BSW also use BSW bolts(screws) to ensure maximum strength.
As for which is better it more of a difference Imperial and SAE standards like SAE and Metric systems. Can drive you nuts on restores.
