For all-out performance, the 16v is better. Around town the 8v is perfect. There is power from low speeds in every gear, whereas the 16v suffers when you're not "on the cam" (screwing it). Yes the torque figures show that the 16v is better in all rev ranges but the gearbox is different and it does affect the drive. The 16v has a much longer 2nd gear, which is why it has such an impressive 0-60 time. Kinda sucks at 30mph in 4th though!
The differences in quoted 0-60 times for the 8v vary because there are two different injection systems involved. Later 8v's used digifant2 and the early ones used K-jet. The 0-60 time for one using k-jet is marginally quicker.
I love my 8v, but a 16v would be nice as something for the weekend!