Two great schools, congrats on all your admits.
I can only speak to Andover from our family experience! My (step) daughter is a lower and absolutely loves it. She is involved in sports, the performing arts (part of a dance troupe called Hypno) and has a diverse group of friends from across the world and varied socio-economic backgrounds.
The lack of school spirit that you mention, we have experienced and observed the absolute opposite at PA. Having gone to many athletic games, family weekends, and dance performances (Grasshoper “G-hop in the fall and Dance Open in the winter) the students absolutely BRING it with enthusiasm, support and spirit…this is to say nothing of the pep rally before A-E weekends, Blue Key Heads hyping everyone up at move-in and all year long at school events. Go Big Blue!
They are building a new music building called Falls Hall that would open while you are a student- fall 2024 according to the timeline, so lots of opportunity there for you as well.
At the end of the day, you need to evaluate based on all the variables/instincts you have- not one person can tell you one is better than the other. No school or experience is perfect, but what you can do is try to make the decision that YOU feel is best for YOU and keeping in mind regardless of what school you end up choosing, you get out of it what you put into it!