Denti -
I think the problem ATCOs have is not that we think TCAS is better than it is - it's the way a
small handful of pilots seem to think that TCAS gives them an idea of the big picture. It is instilled in us ATCOs from a very early stage how innaccurate TCAS can be in the horizontal plane and also the other limitations it has
Point taken about the speed - we often get A/C doing in exceaa of 300kts (as instructed by previous sector) only to have to tell them "when level reduce to holding speed". We find it annoying too!!