From the perspective of someone who only played through the first dungeon last time I attempted the game prior to the 3DS version coming out:
I thought Majora's Mask was fantastic, especially for a Zelda title considering the series has a lot of issues breaking free from the standard formula. The three day system was honestly really easy to work with. Generally exploring an area and accessing/completing the dungeon takes two full three day cycles, although, this doesn't necessarily hold true for anything but the second area/dungeon, as the first area takes less, and the third and fourth areas will take a first time player more. As was already mentioned numerous times, the inverted song of time is your best friend. It halves the flow of time and turns those three days into the equivalent of six. This is what makes the time frame I laid out easily possible. Other than that, this game actually requires you to be a little intuitive. Because there are only four major dungeons, each of them is set up in a fairly non-linear fashion if you don't know what you're doing. After completing all of the dungeons, I can say that completing the dungeon will make you realize just how simple all of them really are, despite how complex they seem when you explore them for the first time. Just recognize that none of the puzzles are very complex, and as long as you pay attention, odds are against you missing anything important.
On the three day system itself: I found it to be great. One thing Zelda games tend to be missing is any sense of urgency. No matter how you slice it, every Zelda game deals with somebody trying to end the world as its known to some degree, some times with a side goal of being ruler of their own world, sometimes because destruction just sounds pretty dang cool. With that in mind, why is it that I can spend the game equivalent of months just gallivanting around the kingdom having a merry old time while the world just keeps ticking on as if there isn't some malevolent force trying to end its existence? Majora's Mask grants that sense of urgency with the people of Clock Town acknowledging that the end is near. It is a core component of the atmosphere of the entire game, and it simply wouldn't be Majora's Mask without it.
Now, you can say "I don't like being forced to refight bosses to pad the game", but you're ignoring the fact that you don't ever have to beat a boss a second time. Absolutely everything that comes with clearing an area of the ill effects brought on by the dungeon bosses is optional except for one thing. Swamp? Clearing it lets you do Koume's target game which you may not even need to go back in time to do. Snowy mountains? All you absolutely need is the powder keg certification, and if you have even five hours left, you have enough time to get it. Besides that, the heart piece in the water, the frog side quest, the Goron race, none of it is absolutely necessary. Great Bay? Clearing it unlocks the easiest minigame around that as long as you have a few hours left on the clock, you have more than enough time to get in one go. Clearing the last temple does absolutely nothing of note to the area, and you're free to leave it behind and never come back. At no point does the game force you to refight any of the bosses in the entire game with the exception being if you didn't have enough time to actually beat it in the prior time cycle.
All the three day cycle really does is make side questing more complex than in any other Zelda game. Certain events only happen at certain times forcing you to pay attention, watch the clock, and prioritize tasks in every three day cycle. At times this was a little frustrating, yes, but more often than not I found myself rushing around and feeling even more accomplished when I would get "x" amount of things done in only a single three day cycle. It felt more rewarding and like it took more skill. I legitimately spent more time side questing than I did completing the main dungeons, and I spent more time on Majora's Mask than I ever did on OoT or other Zelda titles, and not because I was dying or only half completing dungeons in a cycle.
I legitimately feel like the only people that don't like Majora's Mask either suck at it (and blame the three day system for their lack of skill), or rushed through the main story and did next to none of the copious amounts of side questing that really make up the meat of the game.
