We just returned from our Tuscany trip that ended in Rome and I am thrilled to share my experience with a private tour guide that we hired to visit the St. Peter's Basilica, Vatican Museum and the Sistine Chapel.
The company we used was Cris Roman Guide; https://www.crisromanguide.com/. This company is owned by Christina Giannichi and she provided us with a high skilled, knowledgeable and completely wonderful private tour guide named Rosa Militano.
I have visited these sites three times in many years and I've also used a group tour on my last visit. This time, I was completely blown away how much I missed in every visit prior. Rosa was amazing not just in knowledge and details, but she had connections that were invaluable with access to sites that very few people could see. There were numerous times that Rosa approached a security guard and restrictive ropes were lifted and we passed through multiple places.
For the record, this is my personal opinion and I am in no way reimbursed or paid for my comments. I just wanted to share my wonderful experiences that I wished I did years ago. Well worth every penny.