Mercedes are clearly fastest, they got the FL and double points. Ferrari are also behind Lotus so they are the 5th best team. FACT.
Ferrari are very fast, but today they were slightly behind Red Bull and McLaren. Even Vettel said Ferrari was not the quickest today (according to Benson). For both Vettel and Button to catch and stay right behind Alonso for a number of laps despite being in dirty air means they either have faster cars, or they are better drivers. It's very close between McLaren and Ferrari (and Red Bull), but all dry sessions this weekend (P1, P3, Q1, race) pointed to McLaren having the faster car.
Despite having seen the gap was closer, for longer, than I'd previously thought, I would still put Ferrari, McLaren and Red Bull as roughly equal in a space which has very very narrow margins. This season is incredibly competitive!

Ferrari are very fast, but today they were slightly behind Red Bull and McLaren. Even Vettel said Ferrari was not the quickest today (according to Benson). For both Vettel and Button to catch and stay right behind Alonso for a number of laps despite being in dirty air means they either have faster cars, or they are better drivers. It's very close between McLaren and Ferrari (and Red Bull), but all dry sessions this weekend (P1, P3, Q1, race) pointed to McLaren having the faster car.
Anderson: Fernando Alonso's Ferrari was probably the third fastest car in the German Grand Prix yet he won the race from pole position.
Whitmarsh: In Germany, we could catch him and hurt our tyres, but we couldn't get past him. We were a reasonable amount quicker, but if you put someone like Fernando at the front of a race then you are going to have difficulty getting past him
If you have similar cars and one car (Mclaren) drives at 100% then it is going to be quicker at that time than the other car (Ferrari) driving at 95%. Alonso was just controlling the race from the front and saving his tyres, that is why when Button and Vettel got to about 1 sec of him they could not get passed him.