All i want to know is,

At this high bitrate, with these encoders, would the sound be transparent between both formats?

Short answer:
Yes, transparent in both cases for virtually anyone.

Longer answer:
According to various tests, in almost all cases, you could not tell the difference. There are some (rare!) problem samples at this bitrate with mp3 and I'm sure that you could find some for aac, but that's less likely. Anyway, both settings are OK to use if you have to have CBR. Otherwise, use VBR!