PSI used to feed our site with a Cisco 7xxx and changed to a GRF400. The
OpenROUTE Networks RBX250 router we use to talk to it had no problems with
either. Actual packet throughput appears to be improved since the router
was swapped, which I assume was the reason for the replacement. I haven't
noticed a substantial difference in the speed with which the advertisements
roll in. Either upstream box pumped out the BGP advertisements when the
line first comes up at about 60% of the T1. Neither box pushes harder than
that.
There were some problems (non-BGP) when PSI first tried to activate the
GRF, but those appear to have been resolved.