The article is from 2014, but there’s a great overview at Electronic Design of how useful Open Virtual Platforms are.
Also, one interesting highlight from the article related to performance:
The performance of the free OVPsim ranges from 100 MIPS to 1000 MIPS
Picture of circuit board by Fabrizio Sciami (https://flic.kr/p/4NFrtx) licensed under CC-BY-SA (https://creativecommons.org/licenses/by-sa/2.0/)