if the water in the w/a ic system is hotter then the charged air temperature, you sir, have a poor w/a system. Not that it cant happen.

There are a lot of factors to think about. pressure drop, core size, length, piping length, water speed, radiator effeciency. All of it is important.

assuming a good system, comparing core size to core size, an air/water can easily be more efficient. Air sucks at heat excange compared to water (jump in a pool at 60 degrees vs going outside when its 60 degrees).

So at the core side, all things are great.. but once you get to the radiator where the w/a system has to get rid of it's heat, once again we have to rely on air.

as stated once and again, a/a is just easier.

My truck came with a w/a system so I've spent time learning about it and optimizing the best I can. heat reflective materials, bigger coolant lines, faster pump, an additional electric fan, and even a second radiator added to the system.
With all that, I can maintain a HOT side water temp of about 20 degrees over ambient. Thats taking a very hot charge out of a overworked turbo and brining my intake temps down to 120ish at the end of the 1/4. All that without worrying about ice or sprayers.

However, should I wish, I can add some coolant, and get the water down to 30 degrees or so. Again at this point everything is working against it though as the heat exchanger and the intercooler core are both heating it up.

Quite a few drag cars run a w/a system, with no heat exchanger. Rather a tank out back full of ice water. Once it heats up, dump more ice in.

After all is said and done, its a balance of your driving conditions and personal preferences.