An Indonesian study in Diagnostics attempted to make a comparison between Siemens and Roche instrumentation using Peer Group Sigma metrics.
Out of 30 assays, Roche won 29 of 30.
I can't say I wholeheartedly agree with the methodology of the study: peer group data can obscure what individual laboratories experience. The details can get lost in the stew.
However, I can say that our analysis of dozens of individual Siemens and Roche instruments in labs across the USA confirms the broad comparison: Roche beats Siemens. We had a poster at ADLM that confirmed that, among other findings.
Full Diagnostics study is here: https://www.mdpi.com/2075-4418/16/16/2537
[The Sigma comparison table below is our own analysis. Sigmas may be measured higher than 6, but that has no tangible impact on how the method is QC'd. Thus, all values of 6 and higher are rendered here as just plain 6]