People seem to rave over it, and it seems like an OoT clone.I do play it, but what's so great about it?
I'm not entirely sure why you have the opinion that Majora's Mask is a clone of Ocarina of Time. I can understand that they look very similar, but that is due to the fact that they were released within a very short amount of time of each other. Outside of that, I thought that the games felt totally different. Especially due to the difference in what the Ocarina's in each game can do and the time systems.
Obviously, the Ocarina is very similar, but that are similarities with weapons throughout most of the entire Zelda series, so I just see that as a normal thing to do, even more so considering that Majora's Mask is a direct sequel to Ocarina of Time. And then playing it has several different effects that weren't involved in Ocarina of Time, such as playing the Song of Time in different ways caused time to either speed up, slow down or send you back to the start of the first day.
Then you have the other aspects which are quite uncommon to the series, such as being able to battle the bosses again if you wanted too, and sometimes is necessary to continue in the game. Plus the many side quests which expand the length of time that it takes to complete the game, the overall difficulty and how fun that the game actually is. Alongside the side quests that give you useful masks, whereas in Ocarina of Time the masks were there as a sort of thing to mess around with, they didn't really have much use.
The best difference is the ability to use the race masks, it is quite cool to be able to play as the Deku's, Goron's and Zora's, as each had their own special abilities. It adds an entirely unheard of aspect to the series, and one that I don't imagine we will really be seeing again outside of any Majora's Mask remakes.
I won't go on, since I know of many ways in which I find Majora's Mask to be rather different from Ocarina of Time, many of which make the game to be a great game in my opinion, if not an excellent game.