Turbos will run cooler but let's say your giving it some and they are hot and it's starts to rain and you drive though an unavoidable puddle?
As for lag, it would have more but not loads, the guys in the states rub them and they say and show there isn't much lag.
The turbo itself will more than likely run cooler as it's further from the engine. The biggest issue with them is the horrendous amount of lag you add to the system, and having felt the difference removing just 500mm from the intake system makes on a turbo, that's not a particularly appealing thought.
Each to their own though, if you want easy straight line power then go for OT, although I can't see it being much cheaper to give reliable power than a standard system.