Koyo's are excellent, but they are not easy to find, especially locally for most folks. I have a CST 3 core radiator right now, and have been using that one for many years, still goin' strong and probably 100k on it.
Also, you can get a 3 core copper radiator from Napa, it is equipped with the auto trans cooler. Works very well and fits perfectly, both 4 cylinders and V6 setups.