I'm about to implement a VSS using 6509-E. It's a fresh installation and I've got the hardware up and running and have started to read up on the two IOS versions. Some people say "always use the latest version" and some say "use the next newest version just to be sure". I will not need support for FWSM or IDSM, is there some reason for me to stick with SXH rather than SXI3? Both SXH and SXI are labeled as "OK" by Cisco and I see no apparent killer feature in SXI.