I don't really have any experience of SIS as such, but I did have an interview for a position there about 4 years ago and liked the (then) principal. I did not take a position as the salary would not have been sufficient to live comfortably with my family. I definitely would have accepted had it been better paid.
It is a full IB school, which can seem a bit strange if you are new to this, especially the MYP (normally from Y7 to Y11).
Another international school that I would recommend would be EIC (English International College) just East of Marbella, they follow the English curriculum and do IGCSE and A'level. I used to teach there a long time ago (in the 80's), but is very well established and has a good reputation.
My two go there, they are in primary. It's a good school, lots of changes afoot with the new head, but changes for the better I think (hope!). Strong on sports, drama, good 'community' feel too, feels quite 'nurturing' for the little ones. The school is a mix of Spanish and British with a smattering of other nationalities, my only criticism would be the Spanish programme (in primary at least) is poor - my two have barely learnt any Spanish in the two years they have been there. Hope this helps!
Espresso the Lack of spanish is another issue i have with sis. Unless spanish native or living in a spanish Home the Children will hardly speak spanish. My dd is in her 3 year at sis and struggles with sp. Perfect if you are here for a few years with plans to move on or return to uk. Not great if like we plan to stay. Apart from that my dd loves going to School, the way they teach is great and Kids seem happy.
begonia, that really depends on the budget your company or dh wordk gives you. 80% of the people living here live on an expat package. Big budget=villa, smaller budget=townhouse. You find apts in the marina, not so great with children, some urbanisations with townhouses and gardens or villas with private gardens... good luck finding your home!