Here's our statistics for one of the NT IBM 7000 servers:

objects inspected: 2,607,398
objects backed up:    7,118
objects updated:          3
objects rebound:          0
objects deleted:      2,157
objects failed:         269
bytes transferred:   806.08 MB
Data transfer time:   40.68 sec
Network data transfer rate:        20,286.74 KB/sec
Aggregate data transfer rate:         22.55 KB/sec
Objects compressed by:                   47%
Elapsed processing time:            10:09:55

Took 10 hours to back up 800MB! Maybe 1.5 GB an hour is not so bad...