I have this exact same issue and it is driving me nuts. I have two systems running vShpere Client v4.1, one on XP and one on Windows 7 Ultimate 32bit. The XP system the fonts are crystal clear and sharp but the windows 7 system is blurry and a strain on the eyes.
I have tried turning off every appearance effect on windows 7 and it is still blurry.
Can we run vSphere 5 client to manage a v4 ESX environment?
Can we change the default fonts for thie application anywhere?
Dennis