Studio One 3 professioal : Which plugin version should I use? AU VST or VST3 ?

Studio one 3 pro 3.5.4, Mac OS Sierra 10.12.6, MacBook Air (13-inch, 2017), Audient ID14.

I have several double or triple versions of the same plugin in my plugin list. (because they were installed in AU,VST and VST3 on my machine)

It's aoying and I would like to remove the less powerful versions of my computer plugin folders.

Which version should I better keep, AU, VST or VST3?

- regarding audio quality?

- regarding CPU performance?

Thanks.