On using EMC Isilon

Currently, we have a cluster of Dell R730x servers and DAS SSDs to each server. We are considering to buy EMC Isilon 4-6 node cluster to satisfy our storage needs. However, we are debating whether to add more SSDs, buy DAS attached server OR to buy a big 100TB or more EMC Isilon and use it by mounting it on ES cluster nodes via 10GB ethernet. Any ideas about using Isilon SAN with elasticsearch cluster. In particular, ES cluster performance and network delay.