FWIW, I have downloaded all the ticks of both FXCM and dbFX (they have the same API).
Some info for EUR/USD:
FXCM: starting 2007_03_27, 32,392,044 ticks till 2010_01_10
dbFX: starting 2007_08_14, 28,479,968 ticks till 2010_01_10
In general, FXCM has more ticks than dbFX for a specific pair...