When planning a configuration, the main point to keep in mind is that for any given application there are trade-offs in performance, availability, and hardware costs. Experimenting with the different variables is necessary to figure out what works best for your configuration.
Striping generally has the best performance, but it offers no data protection. For write intensive applications, mirroring generally has better performance than RAID5.
What are the availability trade-offs?
Mirroring and RAID5 metadevices both increase data availability, but they both generally have lower performance, especially for write operations. Mirroring does improve random read performance.
What are the hardware cost trade-offs?
RAID5 metadevices have a lower hardware cost than mirroring. Both striped metadevices and concatenated metadevices have no additional hardware cost.