It carries more passengers. Overall, I think the Chimera is an acceptable design- I won't choose it over the M2 Bradley, but I will choose it over the M113.
My main problem is with the Land Raider. First, the designers forgot why the first tanks were shaped the way they did- to cross trenches- and reversed the rhomboid tracks to look cool. This means if the Land Raider has to cross a trench, the reversed tracks will make it bury its nose into the ground, like a giant metal ostrich, and become immobilized.
Then the designers forgot why the first tanks had sponson-mounted weapons- a cannon-armed turret would make the Mark I dangerously top-heavy- and decided to sacrifice the many advantages a rotating turret offers. They even managed to design sponsons inferior to the World War I tank! The Land Raider's laser cannons have exposed cables, meaning shrapnel and stray shots will quickly render the weapons useless- assuming they're not already, what with hanging branches tearing at the cables, lying rocks getting knocked up in the air and down the servomotors, causing notable damage BEFORE the tank reaches the battlefield. What's more, each sponson mounts a single weapon- it doesn't mount two laser cannons, it mounts a "twin-linked" laser cannon, meaning it counts as a single weapon, can only be fired at a single target, and damage to one component will automatically render the others useless!
And this is supposedly so awesome a tank, the Emperor reserved its use for His best soldiers?