I think there _are_ downsides to using open models.

Quality won't be as good. That's a given, at least with SOTA. But there's more: switching between models means qualitative changes in replies, and in strengths and weaknesses on evals. You're also on the "open source track" and there's no guaranteed upgrade path - the creator may simply stop publishing new models. And the fact that they're mostly from China comes with political, provenance, and governance issues.

I think NVIDIA's models are the most promising, because they can serve as a foundation for new model companies. That's a meta-feature that keeps the proprietary models in check. And NVIDIA's incentives are very likely to remain aligned with open-source: they want to encourage competing solutions that rely on their third party hardware.