I'm seeing consistently higher write times on all my mirror servers in comparison to the principals. More specifically the Log writes are almost identical, but the data write is 1-30 times higher depending on the server.

On a server with a mirror send rate of 500KB/s, the Principal '% Disk Time' is 0 and the 'Disk Write Bytes /sec' is 0, However the mirror server '%Disk Time' is %30 and the 'Disk Write Bytes /sec' is 1.4MB/s