For the servers, Clone Wars has a looooooot more little kids on it and usually the events were recycled 'go here, shoot this, go home' in the past. I remember a time when the GMs got so bored themselves there were no events for I think three weeks. This was all months and months back, so it may have changed though. I used to really like the CW server, I've been a commander dozens of different times there by now and I was a SuperAdmin (before Dingo, staff manager at the time, demoted me for 3 days absence. 3 DAYS.)
Meanwhile Warhammer has several events a day which are always engaging and planned out in more than 5 minutes by two admins saying 'let's go shoot stuff', and people seem generally much more mature on it. (It has its problems and people too, every server does.) There's almost always some sort of RP going on, and the server seems to be taken much more seriously. I see actual RP made out of the smallest things, like once an admin accidentally left an NPC spawned on for antlions, and the players turned it into their own event where we drove them back into the forests and started sweeping the planet for the rest of them.
Lore-wise, Warhammer has a deep lore story for almost everything. Every type of enemy, every chapter, every known character, every historical event that was major, all the way back to the dawn of existence. The lore is much more interesting, deep, and engaging than the Star Wars lore.
Most of the Star Wars lore pages on wikis and such are very short. Especially for somethings such as Clone Battalions. Usually just states their purpose, commander, Jedi general, some known members, sources, and known battles.
Meanwhile again in Warhammer, each chapter has what is basically a novel of their history in their Wiki pages, which explains anything about them that you could possibly want to know.
TL;DR, CW server is eh, Warhammer server is great, CW lore is decent, Warhammer lore is awesome.