I have a BE Cooling Aquacoil(Cube radiator), and the fittings are 1/2" OD exactly. They are a nice snug fit with my 1/2" ID braided PVC tubing. They didn't leak one drop with just the hose on there and no clamp.
I put a few layers of teflon tape on there just to make a nice tight seal and it ran for 2 days straight without a single leak. Still no hose clamp(bought the wrong size, DOH!).
I was worried the radiator wouldn't work well with 1/2" ID tubing before I ordered it. But now I'm completely happy with my purchase.
The flow is pretty good out of this unit as well. I got a Danner MagDrive 500 gph pump and I'm starting to wonder if I went a little overboard.
It wasn't much more than the 350gph one, and at least I know I've got lots of headroom in the flow department.