EMC PowerPath for iscsi connection or ESXi emebedded mpio

Hi guys,

for my new ESXi 5.1 server farm i have a lot of server and a big one EMC storage that i need to use with iscsi adapter and for this new setup we are  thinking for use a EMC Power Path  or  do it to ESXi 5.1 mpio.

Which are the real advantage to use EMC Powerpath VS  ESXi 5.1 mpio embedded ?

I'am not sure to use it because have read a lot of problem during ESXi fixing or ESXi upgrade.... There is a real advantage to use it ?

Thanks in advance.