Software Bills of Materials (SBOMs) improve software release transparency by documenting components and dependencies, but their practical value depends on the tools that generate, analyze, and manage them. This paper compares the tool ecosystems of the two dominant SBOM formats: SPDX and CycloneDX. We analyze 108 open-source and 62 proprietary SBOM tools, compare ecosystem-level health metrics across 470 SPDX and 171 CycloneDX tools, examine 36,990 issue reports from open-source tools, and study the top 250 open-source projects using each format. Our results show that CycloneDX-using projects often exhibit stronger developer engagement and selected project health indicators, while SPDX benefits from a larger, more mature tool ecosystem and broader industry adoption. These findings highlight the complementary strengths of both ecosystems and identify opportunities for improving SBOM tooling across formats.