Huawei and ZTE Routers

The other thread about the Alcatel-Lucent routers has been pleasantly delightful. Our organization used to believe that Juniper, Cisco, and Brocade were the only true vendors for carrier grade routing, but now we are going to throw Alcatel-Lucent into the mix. ZTE and Huawei, the big chinese vendors, have also been mentioned to us. I know there are large national security issues with using these vendors in the US, but I know Level3 and other large American vendors use Huawei and ZTE in their networks. How do their products perform? How are they compared to Cisco and Juniper on the performance side of the house? Is their pricing really half or less of that of Cisco and Juniper? Is it worth using these vendors or not worth the hassle?