Yeah - Id expect concert night will always be more busy than the Friday, but once the concert starts you may have shorter lines for rides etc...IDK.
Depending on the act drastically so, and maybe not the usual Universal Crowd - so maybe a reason to avoid it.
Personally, I have not seen a band play there I was even mildly interested in in a long time... and that time was just insane crowds... it was Pat Benatar and I do not think they were at all prepared for the crowds.
It was a total mess.
I think they have it down now, but still adds a lot of folks that would not be there otherwise, so I guess its worth it to Universal.