@ Irene46

That Christina sings off key and strains is not my opinion but a fact which stands on mountains of evidence, and because there are so many performances by Christina both strained and off key...no one's opinion can change that.
If a note is off pitch that is not a matter of opinion, it simply is in tune or isn't. One can argue all day about interpretation and emotion or if a voice is pretty or not, but timing and intonation are two things that can be scientifically measured and thus not up to opinion.