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.

I'd actually suggest looking at

Basically, the cisco AIP comes with an ATM interface. If you buy
the HSSI then you need an ATM CSU/DSU to connect to the ATM network.

My personal opinion is that the cisco AIP is simpler to use.

However, this is not necessarily the case when your objective doing none ATM