460cc Driver Heads : More forgiving. But has the actual fairways hit percentage gone up due? Does anyone have the figures.
Smaller Heads: Smaller sweet spot, but that forces you to increase accuracy and solid contact.
The smaller heads may offer a bit more control to shape shots, but I've found that the larger modern drivers offer move forgiveness on off-center hits.
The larger clubheads allow engineers to increase MOI, which helps reduce side-spin on off-center hits. Going from my TM R7 TP (425cc) to my R11 TP (440cc) has improved distance and fairways hit. The size of the head is likely much less of a factor than the shape and weighting.
There are a few 320cc and 360cc heads still being made.