There is one other major difference which MFGF forgot to mention !
In 7, it is called 7 and in 8, it is called 8 
Not quite...I remember distinctly that in 8.2, Transformer was still branded as 7.4

Though that was before integration in 8.3 onwards
dssd, if you're asking whether there'll be a learning curve for you to go from series 7 to 8, then mfgf is right...other than learning how to use packages for creating cubes (if you were using iqd's from FM/Impromptu), there isn't really much change. You still build your dimensions etc. in the same way.
I haven't had much chance to work with dimension views in 8, so I am not sure how that part changes vis-a-vis Cognos 8 security, but I suspect MFGF's post also partly answers that