Well now, I haven't been to either airport for about five years or so, however, the ATC services at AMS I have found are second to none in Europe.
Yes, the ATC instructions can come quite rapidly, but are usually very precise, just like at FRA.
And, far better than LHR, in my opinion.
LHR just seems (in any number of ways) to slide downhill, ever so slowly.
Quite sad really, as they used to be quite good.