Not too much difference really from first appearances, the Venice boast an improved memory controller and SSE3 instructions which edge out the previous cores slightly in benchmarks.
The true advantage of the Venice is its ability to sustain high clock frequencies, often on less voltage, than its previous cores. The previous 90nm technology had a bit of a bug which kept it reduced to a certain speed, hence why you don't see any 4000+ or FX-55 Winchesters. The Venice core corrected this problem and can operate at those speeds that were beyond the Winnies reach.
Intel C2D E6320 / AMD Athlon X2 3800+
Gigabyte 965P DS3 / DFI nF4 Ultra-D
2GB OCZ Gold PC2-6400 / 2GB OCZ Gold PC4000
eVGA 8800GTS 320MB / eVGA 6800GS 256MB
150GB Raptor / 74GB Raptor
2x500GB / 320GB
OCZ GameXStreme 850w / OCZ StealthXStream 600w