  Recent large language models (LLMs) have been shown to be effective for
misinformation detection. However, the choice of LLMs for experiments varies
widely, leading to uncertain conclusions. In particular, GPT-4 is known to be
strong in this domain, but it is closed source, potentially expensive, and can
show instability between different versions. Meanwhile, alternative LLMs have
given mixed results. In this work, we show that Zephyr-7b presents a
consistently viable alternative, overcoming key limitations of commonly used
approaches like Llama-2 and GPT-3.5. This provides the research community with
a solid open-source option and shows open-source models are gradually catching
up on this task. We then highlight how GPT-3.5 exhibits unstable performance,
such that this very widely used model could provide misleading results in
misinformation detection. Finally, we validate new tools including approaches
to structured output and the latest version of GPT-4 (Turbo), showing they do
not compromise performance, thus unlocking them for future research and
potentially enabling more complex pipelines for misinformation mitigation.
