The Casa Azul, where Frida Kahlo was born, and where she lived on and off with Diego Rivera, is listed in all the guidebooks as a must-visit site. First CRUCIAL piece of advice: do not try to go there and buy a ticket on the spot. You have to do it ahead of time online, or else you will spend 4-6 HOURS not a misprint waiting to get in. I found this out the hard way--I walked over at about 10 am when the museum opens and found two lines snaking their way around the block in two directions, with a gaggle of people near the entrance and no one to tell you where to go. I gave up, and subsequent events convinced me that the only reasonable way to get into the museum is to be on a tour which includes it--the guide will hopefully shepherd you through the mess at the entrance. More on that below.
The Museum is a house and garden and gift shop and cafe. Unless you are following others, you might miss the tiny sign as you go in that tells you to make a hard left immediately into the museum building. In that case, like me, you will spend some time wandering around the pleasant garden more green than flowers, but peaceful and when you try to find how to get into the museum proper hint: not through the gift shop you will find many signs pointing you to the exit and a stairway on which people leave the building--with a sign saying exit only but none pointing you to the entrance.
Finally into the museum: there are two rooms dedicated to a fair number of paintings by Frida Kahlo, and a lot of other people's portraits painted or photo of her. There are some paintings by other painters including, if I recall, Rivera not of Frida. There are some memorabilia and her bedroom, which is made into a kind of shrine to Frida. I knew very little about Frida Kahlo before visiting the museum, other than random images of her as a beautiful and strong woman, including her picture along with Diego Rivera's on the 500 peso bill, and various fleeting references to her, clearly a national heroine. Personally, what I learned from the museum gave me a somewhat sour feeling toward them. But you may come away with a very different reaction.
The reason for the three stars is in part simply my reaction to the museum--it is a perfectly OK museum, but I didn't get much out of it--but also for the difficulty I encountered getting in. My other experiences with Viator/Amigo Tours in Mexico City have been terrific, but I would fault the company for the inadequate information about how and where to start your tour. The confirmation said You will receive tour tickets on hand tomorrow at the Frida Kahlo Museum.
Your entrance Is scheduled at 11:00 , Is recomended to be there at 10:00 .
A representative of Amigo Tours will be there to deliver the tickets, wearing a blue vest with the logo oficial Amigo Tours .
After two other Amigo tours, I still don't know what the logo looks like, and in an environment like the mess at the entrance to Casa Azul you need more information. I was there at 9:45 and no one could tell me how to find the representative--and the only reason I did connect with him in the end was that another American tourist in the same situation called the company on her cellphone at about 10:30 to find out where he was--after a long conversation, she managed to spot him, and I tagged along. In a situation like this, you need the representative to carry a highly visible sign saying AMIGO TOURS, like those you see when you come to international arrivals at any airport.
So rating my own experience, I would say for me it was not worth the trouble--with the emphasis on the trouble the museum is a competent operation once you get in.
The museum itself is fantastic. The collection of art and personal items are great and the courtyard and garden are very enjoyable. Getting into the museum, however, is chaotic and the museum staff did not understand what the Viator pass was nor would they provide any assistance. I purchased this skip-the-line pass when it was brand new to Viator. It is not a skip the line pass. You are pre-purchasing an entrance to the museum for a specific date and time you are not allowed to enter on a different time other than the one specified on the pass nor are you allowed to skip the line. This was not clear from Viator when I initially purchased it. Your pass into the museum will be sent the day before. I've purchased may tours with Viator and have always been very satisfied but for this particular tour I would recommend buying directly from the museum itself so that you can choose your time and have the ticket in hand before you show up to the museum. I would not recommend showing up to the museum without a pass - you will wait in line for hours.