We enjoyed the performance and judged the acting as very good. It is hard not to compare to the movie version, but we tried hard not to! I was impressed with the clever staging - eg. using the real audience as the audience for the the singing festival, and having a Hitler-lookalike 'Nazi' sitting a row away from you. Very well done, indeed.
The casting was really good with 2 exceptions, which distracted us somewhat. The 2 Von Trapp 'boys' were clearly not -- one was a girl, one was much older than the character. Their acting was fine but we kept watching them for the wrong reasons.
Kudos to Maria and the Mother Superior nun - i enjoyed watching them every time they were on stage. And of course, the music was wonderful.
LSR