Can I just give my opinion.
I think some people enjoy a night out in the style of the west end, ie getting cheap drinks, lots of like minded boys and girls, and by 3 or 4am everyone is really pissed and being sick, fighting, etc. This kind of thing goes on in every city centre in the UK. It certainly goes on in Belfast. Also the west end is like the centre of most other holiday resorts on Spain, Greece, Cyprus etc.
The thing that makes Ibiza different from these places are the clubs, DJ's and the people that come to the island. Each to their own, but i think that its pretty stuck up for people to say that its not 'classy' and stuff like that, as its just a lot of bars, cheap drink, and small clubs for young people on holiday to have a drink and a laugh.
I myself will go to the westend, not to fight, but yes, to get ludicrously drunk and have fun. I will also go to the clubs, the reason i am going back to ibiza over anywhere else.