A quick poll:

Are many ISPs taking advantage of SONET APS protection to provide port or router redundancy on short (metro-area) circuits? Or is it more typical to get two circuits and load-share? Or just not bother?

We use APS on all of our circuits both metro and international. Its main benefit is for when routers fail or muxes fail. You can setup SDH to have redundant muxes in different pops also. During maintenance or router software upgrades its a very useful. Neil.