The problem is that we cannot tell wether it is the car or the driver that is slow or fast. Given the huge differences between Alonso and Fisichella, I would say that the Alonso-Renault package is very fast. Schumacher-Ferrari seems slower, but there is also a large gap between Schumacher and Massa.
So one cannot really say anything more than this: Alonso-Renault is faster than Schumacher-Ferrari. One could perhaps add that Fisichella is very fast (Schumacher said so), and that would point to the fact that Alonso really feels good with the Renault.
Another point is that even if everyone is saying that Alonso is cruising, he often says the victory was not easy, that is, he actually had to push hard. So perhaps he is really making the difference. How much of that difference is greater than Schumacher's difference to Massa is a moot point.