I would say that oriental medicine is legit but only when working with a highly trained practitioner. It is much more than mixing up herbs. It normally includes nutritional/dietary regimens, acupuncture, massage, and then some herbal formulas if the former are ineffective.
Diagnoses can be done using western diagnostic tests ranging from bloodwork, urinalyses, and stool samples but also often includes eastern techniques like reading pulse and tongue. From what I understand, reading pulse doesn't just check rate. It checks rhythm, thickness, consistency, and differential between various pulse points. I don't know how that helps with diagnoses though. Those trained in oriental medicine can also read the tongue by looking at things like color, texture, shape, etc... I am not formally trained in oriental medicine so can't tell you much about that either but I have a sense that the extended diagnostic techniques provide means to make a more accurate and effective diagnoses.
What I can tell you is that it worked for me. Instead of simply treating symptoms, it determined the root cause of the illness or abnormality and addressed it, thereby eliminating recurrences. In my experience, I sought out a functional east-west practitioner after recurring bouts of prostatitis that traditional western medicine failed to help with. The western approach was simply prescribing antibiotics. That method was an abject failure and even an insult once I found that the urologist prescribed antibiotics each time despite my UA bacterial culture coming back negative for anything! The antibiotics caused terrible side effects that the urologist then denied being associated with the antibiotic in the first place! Add to that, that the extended period of time for which I took antibiotics destroyed good bacteria, weakened my immune system, invited new infections, and caused add'l digestive issues.
I came off the antibiotics, started a probiotic regimen, changed my diet, sought acupuncture, used herbal anti-inflammatories like pumpkin seed, dandelion, and purslane and am much more comfortable physicall and mentally.
Bear in mind that this is only my experience. I am not formally trained in oriental medicine so cannot voich for its efficacy in treating other ailments but am convinced 110% that for many conditions it is a safer and more effective alternative to traditional western medicine if done by a licensed, trained practitioner of eastern medicine. The other reassurance is that oriental medicine has been practiced and perfected over thousands of years compared to the relatively short time western medicine has.