Cisco's AIP vs HSSI

Can anyone tell me which is better and why? Is there any resources out
there that will help me in that decision.


The AIP has built-in "CSU" functionality.

You can always back-to-back AIPs the way you'd back-to-back HSSI,
but you pay the 'cell tax'...

And the AIP can do 155mbps (- cell tax), I believe.