We are running multiple four node Hyper-V clusters (QLogic Fiber Channel) against a single DSS V6 storage box. It's holding up very nicely. The storage box has 22 600GB 15K SAS drives, and an Adaptec controller with an Adaptec MaxIQ 64Gb SSD cache.
Performance and reliability is excellent.
We moved to DSS from a dedicated EMC CX3-10 SAN.. It was four times as expensive and could not keep up.
DSS now supports multi path IO on Qlogic HBA and it's pretty bullet proof (so far).