Awesome talk. The talk flew by because of the relaxed way you talked, the interesting subject and your in-depth knowledge. I would love to see a part two of this talk where you show some advanced examples of combining multiple usages of second level cache.
I really liked how the talk had a good balance between depth in information and general explaining of common concepts. It was easy to follow and to understand what the talk was about, also for people who have not worked with Doctrine before. For each concept there were clear examples. Well done!