"Hidden" differences between W7 and Vista

[Miraak]

Hey, i am a long time W7 user but i also rly liked vista before, i saw there was alot of progress made by the extended kernel team so i might try vista again soon (at least on my secondary computer)
im quite used to features such as aero peek/snap and other more W7 stuff but i am sure i could manage fine or find the third party alternative

But i would like to know what are the "hidden"/unintended changes between W7 and vista; what i mean by "hidden" are changes that are not already listed or intended by microsoft
For exemple i read on this forum that the D3D/DirectX render quality was diffrent between the two OS, any other differences like that ?

Thx