Bit pushed for time right now, so this will only be quick....I might 'expound' at length at a later date...
We've not noticed much of a decrease in training time so far, but then we've only had one validation since we started using our 360 sim for validation training. In my opinion that's mainly down to two reasons: It's too early to tell (that validation was someone with previous LL TWR experience....ab-initios are still coming through the system), and the task has grown more complex and more difficult, with the layout of the tower and EFPS. Of course, without the sim it would have meant even longer training time, I'm sure, so in a way we are down to semantics.
I believe I mentioned in another thread that until we have HD graphics and perhaps mature DVI technology, any aerodrome sim will have flaws. Even ours, staffed with ten or more on the input side, struggles to keep up with a busy exercise. To be honest, I've only had one session in our 360 sim that felt real. Simulation is still simulation. Radar sims get a lot closer to reality.