I had some experience with the ACFDT-RPA, but despite its promising features it's not practical most of the time, and for that reason, I'm looking for a new method for reference calculations.
QMC is the first alternative for me. Since I'm not familiar with QMC, what are its advantages/disadvantages over ACFDT-RPA? For example, is it computationally more expensive? Is restarting the calculation possible? (it's not possible with the ACFDT-RPA since it's implemented as a post-processing method due to its cost).
Principally, both methods give the exact ground state energy.