Yes. Radiosity is the most correct method of calculating GI. The most people use VRay for interior rendering, because VRay works much faster, and obtained results look realistic - almost like Radiosity render. But 99% companies,spicialized in interior rendering, use Radiosity - because they have enough resources to carry out these huge expensive renderings.But for individual use the best solution is VRay with its ability to provide very good results at acceptable amount of time(i.m.h.o.,of course).
I have slightly different opinion. QMC is good GI solution, but it is only approximation also. To calculate diffuse lighting absolutely correctly, it’s necessary to solve integrals of illumination analitically. But in most cases it’s impossible, and in order to solve these integrals QMC method is used. QMC gives opportunity to solve these integrals as sum of LITTLE quantity of ACCIDENTALLY chosen functions. QMC is method of numerically solving integrals of illumination (not analitically). It means, that QMC method is approximation also.
Besides QMC has one BIG disadvantage: to increase quality of calculations as two times much we need increase size of it (calculations) and rendering time accordingly at four times much. If we want to remove noise, we must pay very high price.All I said was concerned with brute force QMC. Irradiance map method is modification of QMC,it means that irradiance map method is approximation of approximation.It cannot be physically correct (at least like Radiosity). It gives good results, takes less time - but ISN’T AS ACCURATE AS RADIOSITY.
I mean that when we deal with necessity of REALLY good results, QMC isn’t better solution. Of course Radiosity has own disadvantages, but its quality is inimitable.
I’m not impeccable, but results of Radiosity is much better than results of QMC (when you use settings of QMC, which our computers can “swallow”).