What a great problem to have! Well done on getting offers from all three!
I'd recommend reaching out to trainees at all three firms and asking for their insight into things like the work, culture and anything else that might be especially important to you. I would also caution against taking anyone's opinion too literally. Everyone is going to tell you that their firm is the better one but always try to be objective and decide for yourself based on your own views.
PS: I loved everything about Bakers (I'm also obviously heavily biased haha) but the choice is yours!