We visited the Old Globe theatre to see "A Gentleman's Guide to Love and Murder" and it was a wonderful experience. The show was very funny and cleverly written and we both enjoyed it very much. The Old Globe is a beautiful theatre and well worth a visit. We walked across the bridge into Balboa park and all lit up at night it was a beautiful sight. I did have some difficulty purchasing tickets online from Australia as the website would not accept an Australian address so I ended up putting in a friends US address and then it was fine. I just picked the tickets up at the box office so it didn't actually need my address. I did eventually ask them via email to change that and they did.
Our tickets were incredibly cheap (I think $35 each) for far right seats near the front but there don't appear to be any bad seats so we were happy with the cheaper price. We also secured a discount at Inn at the Park via the Globe Theatre website so look out for the promo code before booking accommodation.
"A Gentleman's Guide to Love and Murder" finished shortly after our visit but if you see this show somewhere else and you enjoy musical theatre I would highly recommend it.