Hopefully, I'll find out on Friday. GHE heading for roosters. So far, I have only had extractors. My first thought on the question is:
Potential problems increase in direct proportion to the number of parts.
Extractor - two parts (if you include the screw)
Ejectors - lost count after 15, some are one-offs but others count twice. Somebody else will know the total but it's way more than 2.
That said, I haven't any experience with them and haven't heard much on the discussion forum about ejector problems. Seems Mr. Parker ran a quality enterprise.