(4) According to the critics the MTV

According to the critics the MTV awards ceremony was tasteless, but according to the audience it was better than ever.

Is the sentence correct?

yes

According to the critics the MTV awards ceremony was tasteless and according to the audience it was better than ever.

Is it still correct?
If correct which one is the best?

It’s still correct.

The choice of which fits best depends on overall context and personal choice. Because in this case you are comparing two opposing reactions to an event, ‘but’ is the option which would usually be used. However, this really would depend on what was said previously.