I've only done Reading of the ones you mention so can only compare with that. Bracknell is not quite as fast. It's fairly flat but has a couple of gradients, one a bit taxing on the legs at about miles 8 to 9 and some other smaller climbs. Nothing dramatic though. Lots of twists and turns, underpasses etc - it is Bracknell, after all and not scenic but not as bad as you might think. I'd say add a couple of minutes onto your Reading time. Note also the time of year. Bracknell takes place at the start of the warmer weather and has in the past been held on its own one-day heatwave.