I noticed that we have posted a really good summary of the above points through the new fast publish system for KBs. (Note the disclaimer at the bottom which is not normally shown on full KBs). There are some really good points here to consider about setting up and configuring a mirroring environment.
Things to consider when setting up database mirroring in SQL Server.
In addition to this of course, you should remember my previous points made on this blog about Virtual Log File fragmentation which I recently saw in a production environment again.
1413 error when starting Database Mirroring – How many virtual log files is too many?
Slow recovery times and slow performance due to large numbers of Virtual Log Files