Does Afinitor work for metastatic breast cancer?

I am about to start my third line of treatment for metastatic breast cancer. Ibrance worked for 15 months followed by Piqray/Truqap for two years. Truqap has lost its effectiveness, and two options were considered: Afinitor with fulvestrant or Xeloda oral chemo. I opted for Afinitor and would like to hear from others re: side effects, effectiveness, etc. Thanks.