If you are concerned about the CPU footprint of storage on your ESXi hosts, I'd go with the offload. Since most hosts I've encountered have plenty of CPU to spare, and the swiscsi configuration is simpler, I tend to go with that. That said, I have no experience with the EQLMEM plugin, so I don't know if there are other benefits beyond the offload.
I'd check to see how a configuration with the offload handles an iSCSI multipathing configuration. That's where things tend to get a little strange.