One thing determines my choice of aircraft if I have one – the internal configuration. I use seatexpert and seatguru to check that out, and given airlines often refresh products on cycles that mean some aircraft benefit before others (e.g. BA putting NGCW on 747s before 777s), that is the deciding factor.
I do have a soft spot for 747s, simply for the nose cabin and upper deck, for twin engine wide bodied aircraft it’s the 777 over the A330. Single aisle it’s A320 series over 737 because of cabin width.