This paper presents a Benchmark Intended Grouping of Open Speech (BIGOS), a new corpus designed for Polish Automatic Speech Recognition (ASR) systems. This initial version of the benchmark leverages 1,900 audio recordings from 71 distinct speakers, sourced from 10 publicly available speech corpora. Three proprietary ASR systems and five open-source ASR systems were evaluated on a diverse set of recordings and the corresponding original transcriptions. Interestingly, it was found that the performance of the latest open-source models is on par with that of more established commercial services. Furthermore, a significant influence of the model size on system accuracy was observed, as well as a decrease in scenarios involving highly specialized or spontaneous speech. The challenges of using public datasets for ASR evaluation purposes and the limitations based on this inaugural benchmark are critically discussed, along with recommendations for future research. BIGOS corpus and associated tools that facilitate replication and customization of the benchmark are made publicly available.