Hi smartshopper,
Both Latex International and Radium make very high quality Talalay latex in both blended and 100% natural versions as well as various specialty formulations such as gel infused Talalay. Latex International has a bigger market share in North America and Radium is more common in Europe although you will find Talalay latex made by both manufacturers in North America.
Some of the manufacturers I know tend to lean towards Radium because their latex has been more consistent and had fewer quality control issues over the last few years (see post #2 here) but LI appears to have addressed the sporadic quality issues that they have had and this doesn’t seem to be an issue any longer so in “real life” terms I would treat them as equals.
Phoenix