The short version
PlatinumLED wins on most spec and brand axes; BioLight wins on price. The decision is whether the extra spectrum, testing transparency and brand depth justify $100 over BioLight.
When PlatinumLED BIOMAX 600 is the right pick
If you want the broadest wavelength coverage in the mid-tier, published third-party EMF testing and the more mature brand, PlatinumLED is the right shape. Most spec-focused mid-tier buyers land here.
When BioLight Pro 900 is the right pick
If you want competent four-wavelength mid-size coverage at the lowest mid-tier price and brand maturity is not deciding, BioLight is the right shape. Solid value play at $899.