Using it here on production since the last 3 years, no problems so far. iscsi and nfs shares.

2 servers on supermicro x10srl with xeon E5-2603 v3 @ 1.60GHz , 128Gb ram each, 2 intel ssd for zil 2 ssd for l2arc, 16 sata disks. using ibm 1015hba's flashed as 'it' mode.
I had to tune it a lot to get best performance both on the nodes and on the storage side, sysctl. no rule of tumb. also many changes at hand to get full multipath, failover, queue depth, reqs, io schedulers, etc.   

network cards, all Intel.

regards,