I’m glad people are sharing their info here. We have, however, decided to skip Puebla and just stay in Oaxaca for 10 days and will then fly to Mexico City for 8 days. We’re pleased with the decision, preferring to keep this trip slow and easy.

If you spend 10 whole days in the state of Oaxaca, you probably would have plenty to do. As of now I have 4 nights/ 3 whole in Oaxaca city, 3 nights in Puebla city, and 8 nights in Mexico city. Am I making a mistake by not spending more time in the state of Oaxaca and skipping Puebla?

Puebla is wonderful (we preferred it to Oaxaca, though they are hard to compare because so different), don't worry! But ultimately we each need to decide for ourselves...you won't know until you go.

Thanks, we're both happy with the choice. We were looking to take it easy with a longer stay and relaxing into a place. I'm sure we would've enjoyed Puebla but I'm pretty hopeful we're going to enjoy our stay in Oaxaca, too. We stayed in Savannah for 10 days last year at the same time, and we loved it. It's that slowing down that I'm looking to replicate. Of course, we'll tour the area, but explore one place. And then we'll have 8 days in Mexico City! I'm getting excited!

No one will know in the end but you. Why not post on your own trip planning thread? Then people will have a better idea of what your interests are (seemingly just museums and ancient sites).
My impression of Oaxaca was that it would appeal to Western tourists who like galleries, upscale dining and shopping. Puebla was less overtly "touristy" and definitely "cheaper". The Baroque architecture was unique as well as the multi colored churches. I felt it was a more interesting city for street photography.

I like seeing various cities and enjoyed Puebla a lot.

AA has flights from both Oaxaca and Puebla to the US (DFW or IAH probably), which I wanted, I had a horrible flight going to Oaxaca transferring in Mexico City. I think it was on Volaris (the part from MEX).