ZFS on Linux seems to be very stable for me.
Bear in mind that with LIO you will be able to use SRP only with CentOS inbox drivers. If you choose to install Mellanox OFED, you will have access only to iSER over LIO. The only way to have SRP with Mellanox OFED is using SCST.
I actually conducted some tests comparing VMware storage performance of SRP over LIO/Inbox, iSER over LIO/Inbox, iSER over LIO/OFED, SRP over SCST/OFED and iSER over SCST/OFED. In all tests SCST/OFED performed consistently better than ILO, with SRP over SCST/OFED being the best latency-wise and iSER over SCST/OFED bandwidth-wise.