It all depends on how the application is executed.

Air/water:
you need a signifigant heat exchanger. Any heat sources near any of the lines will effect the water temp. Once stopped, your bound to heat-soak the water. It takes a lot more time to cool down a gallon or two of water then just the air/air heat exchanger.
If you take measures, with fans and large heat exchangers, w/a can work well on the street. But if you flog it, then let it sit while your munchin a burger, expect that water to be nice and toasty when you start her up again.

However, at the track its hard to beat. Because you can super cool the liquid with ice and other means.


Air/Air:
Great for jump in and stab it situations. The only thing getting hot is the piping and the heat exchanger. Although an issue to concern yourself with, measures to keep the piping away or sheild it from heat sources help a lot. No need to cool down lots of water, and you'll get pretty consistant intake temps based on ambient air temp.

A/A can be super cooled as well, but you'd need to use a sprayer/fogger of sorts to spray a compressed gas onto the heat exchanger. (basically replacing the ambiant air flowing over it with colder air)

Its really a toss up, it seems like whatever a turbo car came with, aftermaret preference is for the oposite method.