BEM is a methodology that I started working with and while it had great potential and I liked the idea. In reality BEM caused more issues with removing the cascading part of CSS.
Eventually SMACSS was a much better solution paired with BEM but restricted to being used only in modular type features, such as a sliders or tabs etc. However even then BEM caused other issues when used within LESS and SASS because of nesting. Ultimately BEM ended up being the cause of more problems than it resolved.
That being said it would be suitable for a site that doesn’t use SASS or LESS but needs some organisation.