Well vanilla ODE solvers are a dime a dozen. Sufficiently optimized stiff ODE solvers tend to get around the same efficiency, with some methods doing better on

Well vanilla ODE solvers are a dime a dozen. Sufficiently optimized stiff ODE solvers tend to get around the same efficiency, with some methods doing better on some problems, and others doing better on other problems. So it's all problem dependent and this is just one implicit RK method, while things like ARKODE already have quite a few, FATODE has quite a few, and DifferentialEquations.jl has quite a few, etc, meaning I wouldn't expect it to be too different. What would make it exciting to play with if it added something. Free parallelism or uses the Xeon Phi automatically, complex number support, event handling (many examples where this is necessary. One: PDE solvers need this for adding projection steps). But since development has halted, we're pretty much guaranteed that none of this will ever come.