Hi,
We stayed near to San Miguel on our first visit to Ibiza, and we found that the beach there gets a bit crowded. We preferred to drive to Benirras beach, which is only about 5 minutes away, and now that the road has been improved, it is not such a pain to get to. There are a couple of nice restaurants at Benirras as well.
Going out in the evenings can be a bit of a pain, we found we usually had to drive elsewhere on the island to find decent restaurants, although we did try the one right at the far end of the beach at San Miguel. This was quite nice if I remember.
Hope this helps! Have a great time!