I purchased Cubase VST 3.7 and then I upgraded to VST/32 5.0 and then I upgraded to Cubase SX and then I crossgraded to Nuendo2.
I personally always hated Cubase VST because I am more comfortable with Windows-type of environment and with mouse clicks. I usually do not like keyboard short cuts and undocumented features that are not explicitly available at the menus.
So Cubase SX came and I fall in love with it. It solved the problems with VST. All features are in the menus. If you want them, you use the mouse to select them. The unlimited undo feature is alone worth it.
Everybody agrees that SX is easier than VST EXCEPT if you are already comfortable with VST, you will struggle with SX. Not just SX but any software other than VST. And that is my point: I never became comfortable with VST to miss any part of it. This means that for a neutral person, SX is easier to use. For you, it really means that you need time to adapt.
However, there is another problem with SX. Since SX was rewritten from scratch (using Nuendo as a skeleton), many features in VST are not in SX. The answer for this is to skip SX and go to SX2.
I have found out the following:
1) Those people who loved VST and hated SX, actually loved SX2.
2) Those people who loved SX also loved SX2.
3) Many people who hated both, loved SX2.
The conclusion: Upgrade to SX2!!!!
One problem with SX2, it requires more computer processing. If your computer is older one, postponing your purchase might be wise.