At the moment I can only speak of my own band´s recording, all other productions I did had pretty different sounds left and right.
We play more rock-ish music, but the instrumental parts are reaching from punk to metal.
It´s not exactly the same for left and right, but very close.
My own sound comes from a 2x12 with Eminence Wizard & Red Fang. They sound very similar, more so than sometimes two speakers of the same model do. Recorded with 4 different mics (2 each). One speaker to the left, the other to the right with a different take.
Each mic got its own EQ treatment for cutting fizz. It´s really different for each of them, and the result is better than just using EQ on the sum.
The rest of the chain stays the same, just different speakers.
My fellow guitarist didn´t doubletrack his parts. 3 mics: one panned center, one left, one right. On the same speaker, the result is close to identical for both sides, but not exactly the same.
+ it´s a lot more coherent with similar sounds
+ less of a hassle to set up
+ needs an amp / cab less
- the "wall of doubletracked guitars" feels a tad less wide. Just a tiny bit when you have a small difference in sounds, maybe a bit more so when they are the same. (The wideness mostly comes from the doubletracking)