We were there with the family last New Year, and spent the eve at La font de Gaul in Pollensa. While the atmosphere was good, we didn't enjoy the food which was bland. however at midnight we went down to the square in Pollensa and enjoyed the celebrations and fireworks there. It was very pleasant and free from any roudyness which you might find in the UK.
We then went back home and celebrated one hour later for the British New Year.
I guess you have heard about the Spanish tradition of eating 12 grapes as the clock strikes twelve - one on each stroke. A tip - don't use ordinary grapes as Spanish ones have seeds. You can buy tins in which there are twelve seedless grapes, especially for the occasion.
The weather was lovely and my daughters even claimed they got a suntan - but you had to look very hard!
Roy