In this situation, holding a pair of Aces in the middle position, facing a 3-bet from UTG or UTG+1, I would definitely choose to raise. A 3-bet from early position players typically indicates a strong hand, and since we have the best starting hand pre-flop, it's important to get value from our opponents while we still have the best hand.
By re-raising, we can put more pressure on our opponents and force them to either fold their weaker
hands or call with a worse hand, which increases our chances of winning the pot. However, the size of our raise will depend on the stack sizes and the dynamics of the table. If our opponents have deep stacks, we can consider a larger raise, while a smaller raise might be more appropriate if the stacks are shallow.
In summary, I would choose to
raise with a pair of Aces in this situation to maximize the value of our hand and put pressure on our opponent.