San An really isn't that bad a place. It's lively and caters for a pretty broad spectrum of wallets and tastes. For those that are petrified by the potential cost of an Ibiza holiday, it helps make the island more affordable and accessible.
For me, my only problem with San An is that it does tend to attract more (not all) of the 'less music-driven', British 'drinking' crowds. I have no problem with that crowd per se and I don't think there's too much wrong with providing a market for that if it helps make the island more dynamic and varied. But if you go to San An on the ‘package holiday' experience, as I found, it can be really easy to get trapped in San An – or at least feel trapped if you aren't really part of that crowd.
The San An nightlife, for me, was fun, endearing, almost weirdly nostalgic to begin with. For the more ‘clubbing-orientated' Ibiza goer, it doesn't take long to feel like you want a bit more though.
Doesn't make San An a bad place though.