VX SS series 2 is the way to go. VY not as eye pleasing as the VX sexy curves. However Vy is newer car probably less problems due to its younger age.
We are talking 6 months difference between a VX Series II and a VY Series I. In fact in a lot of cases the Series II VX would have been sold/registered after some series I VYs had been sold.
So age wise, consider them the same.
Guess it depends on what the OP wants. With VX being slightly cheaper, it does allow more cash for mods. I agree the VY interior is much cleaner....
But I would rather have a VX Series II with VY Gearknob, Handbrake, Pedals, HDB Steering Wheel, Metal Door Handles + Airvents and matched with a VX HSV Senator Cluster.
NOTE: I have the VX Senator Cluster to go in, just waiting on Doctor Bob to reprogram it. I am also trying to track down a new HBD VY White/Black Leather Steering Wheel.
So depending on the price difference of the cars, you could easily upgrade the VX interior to look a bit like the VY...
VY Interior with VX exterior....