Whose team is better?

Team A is better, simply because of the levels. Just train all of team B up to level 100, and you'll have np probelm beating team A.

I say team b is better

Team A
Charizard replace hyper beam with heat wave and give it earthquake in place of blast burn and dragon claw in place of fly

Mewtwo replace safegaurd with calm mind

Moltres replace over heat with heat wave

Articuno should have ice beam, mind reader, sheer cold and fly

Team B

Salamence replace dragon breath with flamethrower

Tyranitar replace surf and thrash

Gengar replace strength with hypnosis and destiny bond with dream eater

Charizard replace blast burn with earthquake and steel wing with dragon claw

Mewtwo replace strength with ice beam and swift with thunder bolt

Team A 7/10

Team B 8/10

So I would was team B is better.

Hope I help

A Team:
Well it is mostly legendaries and there are little type advantages over other types. So I must give it a 7.2.

B Team:
This team, however, has many different types of Pokemon. Using these strong Pokemon over the other team would completely annihilate because of the many type advantages this team has. I would give this team 9.8!