If you aren’t reading Sam Williams’s blog A Critique of Crisis Theory, you need to start. He’s serializing an interrelated set of essays on Marxist theories of capitalist crisis that are brilliant in their depth, scope, and informativeness. Even if you don’t know much about Marxist economics, he’ll help you understand the essential concepts (anyone who really wants to get acquainted with Marxist economics would also do well to read Capital while following along with David Harvey’s course).
A particular gem is this piece, “Value Theory, the Transformation Problem and Crisis Theory”, which shreds the basis of the out-of-hand dismissal of Marx by neoclassical economics, including the common belief that Marx’s economics cannot solve the transformation problem. He also provocatively claims that Sraffa’s critique of the mathematics of neoclassical economics can be appropriated by Marxists without having to capitulate to his rejection of the labor theory of value.