It ultimately depends on your agni (digestion power). If you have a strong digestive system then you can enjoy the additional Vitamin B of brown rice. But if you feel otherwise then stick with white, as its easier to digest. If your not able to judge then go in for white during summer and brown during winter as your agni is weaker and stronger respectively.
There’s a lot said about how brown rice is better than white, where the latter aids weight gain and has low nutritional value. But ayurveda says that rice reacts differently to ever body type and the type of rice doesn’t actually matter. Nevertheless, rice according to ayurveda is good for everybody immaterial of your constitution. With rice it really depends in the individuals agni, which includes several digestion related factors.
Another major factor that decides how rice is digested is how its processed, instant and precooked rice are often coated with glucose, making it difficult to digest.
The best way to go about this would be to consume white rice in the summer, when your agni is naturally weak. And go in for brown rice in the winter, when your agni is at its peak. Its also about knowing your digestive strength because brown rice has an extra layer of bran which takes more time and energy to digest. So if you already have a weak digestive system then stick with white or you can go ahead and enjoy the additional Vitamin B that brown rice has to offer.