Hmm, it depends on your feet (mine are quite wide).
For me Fila are as they should be (UK size 9 to 9.5 fits), Adidas fit a size small (always go for 10s in Adidas, this is the case for Barricade Vs, Tirand IIIs and Ambition IVs) and Nike seemed to be smaller than that (tried on some City Courts a while ago, I tried a 10 and they were too small).
Best to try some on in a shop and see how each brand fits, then you can mail order stuff with a little more confidence.