As like there are offers in Europe to try several kinds of beer, there are sake comparing, sake tasting offered in Japan too. It usually comes in 3 small glasses with 3 different types of sake.
Types of sake is not divided by which rice was used but what kind of ingredients were used and the rice polishing ratio. There are three ingredients; water, koji rice and distilled alcohol. However, not all use distilled alcohol for producing the sake. Type of sake which has Junmai as prefix does not use distilled alcohol and therefore it is genuine type of sake. By the way, koji rice is a rice mixed with fermentation starter called koji. The rice is steamed and then koji is added to the rice.
Then, the polishing ratio of the rice is very important too. If the ration is less than 60%, the sake can be called ginjo. If the ration is more than 50%, it can be called daiginjo. The sake which use distilled alcohol but used koji rice and the ration is less than 70% is called honjozo.
Therefore there are generally 6 types of sake = shu. Honjozo-shu - including distilled alcohol but ration is less than 70%. Junmaishu - does not include distilled alcohol but the ratio does not care. Ginjo-shu - the ration is less than 60% but includes distilled alcohol. Junmai ginjo-shu - ginjo type without distilled alcohol. Daiginyo-shu - the ratio is less than 50% but includes distilled alcohol. Junmai daiginjo-shu - daigijo type without distilled alcohol. Of course the prices go up if the ratio goes down.
It is very complicated but may be it is similar to whiskey, which can be single malt or blended whiskey. There are people who love blended whiskey than single malt one. Therefore you cannot say Junmai daiginjo is better than daiginjo.
Anyway, if you like sake and you are in Japan, try to find out which sake fits you!