The Xtina fans are really something. They're using their egos instead of their ears.
Bey is a technically superior singer. Her control is amazing. Her resonance is jaw-dropping. Her sense of pitch is so acute. She has a decent range which she can actually PROPERLY use.
Just because Bey is underrated vocally and people
used to give Xtina honorary tiles (back when she could actually sing) those mean NOTHING today.
Today, half of Xtina's performances are rough, out of tune, made worse with poor technique and general INsensitivity when it comes to applying vocal techniques such as runs and riffs.
Bey, on the other hand, has less to work with (people say xtina has a wider range and I'll just take that as true) but she spends a lot of time making sure she actually sounds GOOD. When is the last time Bey belted some off-pitch, poorly supported, raspy note? Yeah.
Take it from me. I really have no personal bias for or against either of them, but as a trained singer in an intermediate/advanced choir, I know amazing singing when I hear it.
Don't let the past fool you, Xtina stans. Her glory days are long over. Of course, her NBA performance slayed me and she can always recover from her mis-steps in the past.
Peace!
Radio agrees 
I hope she proves me wrong but she's kinda eh w/o Ethan's production imo.