vSphere 6 – New Config Maximums etc.

vSphere 6 Doubles the vSphere Maximums:
64 hosts per cluster (vSphere 5.x it was 32)
8000 VMs (previously 4000)
480 CPUs (vSphere 5.x it was 320 CPUs)
12 TB of RAM (vSphere 5.x it was 4 TB of RAM)
2048 VMs per host (vSphere 5.x it was 512 VMs).

on Some blogs maximum VMs per cluster still listed as 6000, that information is based on beta builds.....for more info take a look here : vSphere 6 – Clarifying the misinformation

VMs get a little bigger as well:

Virtual hardware 11 (vmx11),  newly released on vSphere 6
128vCPUs
4TB of RAM (NUMA aware)
VDDM 1.1 GDI acceleration
xHCI 1.0 controller compatible with OS X 10.8 + xHCI driver.

Note: It will be possible to use vSphere C# client to view functionality in virtual hardware 9, 10 and 11. Editing of settings will be possible in vmx8 and access to view settings virtual hardware 9 and higher.

Also the C# client in the final release of vSphere 6.0 will be able to manage vCenter.

FT Features: 

4vCPU VMs can be protected by FT

VMs with up to 64Gb of RAM

Up to 4 FT protected VMs per host

Hot configured FT possibility

Enhanced virtual disk format support

VADP support (can backup FT protected VMs now. Previously not possible) 

Configuration Maximums vCenter Server 6 on Windows or Linux based VCSA:

As the limits increased so now minimum requirement of RAM for vCSA is 8GB and in this configuration you can run up to 20 hosts with total 400 VMs.  Take a look of below table for different sizes of the appliance. The size can easily be adjusted during the deployment process.

vSphere6.0 Linked mode comparison:

That's it....yes i know there are many more things ;)