I thought some of the misprints were very easy to spot (indeed they shouted out where they were) while others were so contrived I struggled to work them out even when I had the answer.
I couldn't really see the point of the misprints. Normally a clue gimmick conveys essential, or at least helpful information to enable the solver to complete the puzzle, but these weren't necessary at all. If one fails to work out some of the correct letters it makes no difference whatsoever, and it is almost impossible to make sense of them until one has the them anyway.