An important first question to ask about all rice - and for that matter, most foods - is: "how much has the rice been processed?" In the case of rice, processing usually involves milling and polishing. The outermost layer of rice, called the hull, is removed to make brown rice. Brown rice is rice with the whole kernel intact and the kernel is still surrounded by all layers of bran. To produce white rice, the bran layers of the rice have to be milled off. Most of the rice germ is also removed during this abrasive grinding process. At this point in the process the rice is called milled, unpolished white rice. Finally, a wire brush machine is used to remove the aleurone layer that remains on the rice. This step is called polishing. Polishing is not an all-or-nothing process, and semi-polished rice may still contain parts of its aleurone layer.
The bran, germ, and aleurone layers of rice contain most of the fat content found in rice and is the source of fat-soluble vitamins like vitamin E as well as many other nutrients. If the high-fat components of the rice grain are left intact, the shelf life of the rice greatly declines and this is partly (if not largely) the motivation for manufacturers to remove the bran, germ and aleurone layers of rice thereby reducing its nutritional value..
There is a processing technique called conversion that results in "converted rice". Converted rice is produced by steaming the whole grain before milling, causing some of the B vitamins to migrate from the outside layers into the starchy center of the rice (called the endosperm). This process leaves some B vitamins inside the converted rice even though the manufacturers remove the outside layers, but this version is still not your best choice. The most nutritious rice is always whole grain, minimally milled and unpolished (or semi-polished) with its outer layers intact. You want the rice bran and the rice germ when you consume rice!
Basmati rice is a unique species of rice originating from India. Just like all species of rice, basmati is available in white or brown versions, depending on the extent of the milling process. Like jasmine rice, it has its own unique smell. In the case of basmati, this smell is due to the presence of a chemical called 2-acetyl-1-pyrroline, which is found in basmati rice at about 90 parts per billion. That's about 12 times more than other rice giving basmati its special aroma. Brown basmati rice is comparable to other types of brown rice in nutrient content, and white basmati rice is comparable to other types of white rice.
Most brown rice - basmati or otherwise - are better nutritional choices than white rice because of their increased fiber content. Brown basmati rice contains about 20% more fiber compared to other types of brown rice.