well ccna is mostly about thier routers. now when someone has a 3com ir foundry or extreme or juniper or other brand a CCNA isnt gonna matter. its a propriatary cert. and only used for thier products. the only semester in cisco acad. that was any good for genreral networking was the first. the rest were all about the IOS (Internetworking Operating System)!!
and not everyone uses cisco
most of the bigger webhosts and datacenters use juniper networks routers and 3com or foundry switches. cisco is mostly used for switching in half of teh top 25 webhosts with thier own datacenters
also 5 of the top 50 use foundry routers. while of that list 30 use juniper routers and cisco and foundry switches!
would go for a brand neutral certification thats whoes I have knowledge beyond cisco.