Apollo Justice is underrated and overhated. I think a lot of people felt the same as you about the plot shift and it has some lingering bitchiness surrounding it, but imo it's got some fun stories in it. AA1 and 3 are superior but its better than 2 for sure.
Dual Destinies... I played it but never finished it. I dunno, I really wasn't feeling it by the time I hit the case in the space center. It's a really nice looking game, but everything outside of that just kind of felt off about it. Particularly Phoenix being there and pretty much just being his AA1-3 self again despite everything that happened previously.
Never played Spirit of Justice
I pray god will curse the writer, as the writer has cursed the world with this beautiful, stupendous creation, terrible in its simplicity, irresistible in truth