The VMware vSphere Web Client is the place to be, there are more and more third party plug-ins that's only released for this, and not for the legacy old vSphere Client.
So I was looking for some tricks for VMware vSphere Web Client, so I could demonstrate some nice features at my customers.
First step in optimizing the vSphere Web Client server is upgrade to newest version, performance has improved in version 5.5, and make sure that the Server running it have enough resources, no memory swapping and low "CPU Ready Time".
For the Browser you can increase the Adobe Flash Cache setting for your vSphere Web Client Server, see William Lams article about this here.
Also remember to install the VMware-ClientIntegrationPlugin.
William Lam also did a very nice article with some handy short cuts: