Wow. Well, I'm not sure I'm the most qualified person to try to convince you, but I've certainly built up a lot of time on the franchise, so I'll try to put it in as favorable a light as I can
First off, this game I find takes a certain mindset to play. Too often, I hear people complaining that they don't like the game, but they usually fall into one of two general categories. The first category is that "it's boring". This usually comes from individuals who have tried the game for maybe half an hour to even several hours before chucking it. Indeed, the game is slow in the beginning. This is because it's a huge game, and the developers are trying to give you an easy transition to give you all the skills you'll need. The game starts out by introducing you to the various elements to the game, and invariably, it begins with herb gathering and perhaps slaying several very minor, herbivorous creatures. It touches on the several different mission types, the crafting system, etc., but the problem is, this can take several hours to go through for a player who is brand new to the franchise. Once you've past the initial 'tutorial' quests, the game opens up quite nicely.
The second complaint, from those who have managed to get past the tutorials, is usually regarding the difficulty, or any perceived weaknesses the combat system may have. Previous to MH3U, a lot of the complaints were centred on the fact that there was no 'lock-on' feature. I'll get to the combat mechanics shortly. Truth be told, if you dislike challenge in your games (and by that, I mean some pretty significant challenge, at times), Monster Hunter may not be for you.
Monster Hunter is a game of 'skill', rather than 'numbers'. In many other games, you level up, making it easier to damage enemies, and gaining equipment with higher attack modifiers helps to that end. This essentially gives whoever has the higher 'number' or stat, a distinct advantage. With Monster Hunter, such numbers are mostly irrelevant. A player just starting out could be given the highest end-game equipment, and still be made into mincemeat by one of the lower monsters, because the numbers afforded them by the equipment can't overcome the lack of skill. This is the reason for the learning curve. Monster Hunter slowly pits you up against gradually more difficult monsters, so that you gain an understanding of combat mechanics by the time you hit end-game.
You have, on average, 45 minutes to complete a mission, regardless of what that mission is. Sometimes, if the monster is very hard, it takes all that time to kill it. Other times, it might only take 10 minutes to finish everything. Monsters all have their own tells, their own 'quirks' that signal they're about to do certain things. You get a feel for them, and learn whether you can risk an attack, or need to block or dodge. You also get a feel for the different weapons, as they all have their own mechanics, their own strengths and weaknesses. There's no greater feeling than slaying a monster by the skin of your teeth after dodging a potentially fatal blow.
One of the biggest draws of Monster Hunter, aside from the epic monster fights, is the accumulation of items. If you're a pack-rat, and love to just collect things, it might attract you for just that purpose. There are so many different items, you can get lost just in your farm, hunting for bugs, fishing, mining, planting your fields (though I understand that this isn't a feature in MH3U, it's likely something similar). The monsters all have their own parts as well, from wings to tails, bones and scales. When you kill a monster, you can carve the pieces right out of their body and add them to your collection. Items like monster parts are used in the crafting system, and there are more pieces of equipment than items! Weapons can be upgraded, and take different forms, and armor can be made stronger. It's just such an amazing element of the game, and it'll keep you fighting monsters over and over again, just to get all their related equipment.
I really can't say enough good things about the series. It's such a huge game, I easily put on several hundred hours for each installment in the franchise. That said, like I mentioned before, it's a game that presents plenty of challenges, but appeals to the item fanatic. It may or may not be your thing (I think Animal Crossing is quite a few worlds away from MH, but I do recall item collecting in that game, so it might be closer after all), but I think it's certainly worth picking up. A final word, however, is that you may want to find someone else to pick up the game with you. Monster Hunter can support up to four players on a single hunt - and it's a game aimed at co-op, though solo play is certainly doable - and not only does having more people with you speed things up, but the social aspect makes things much more fun. I found that while I spent nearly 700 hours playing solo across all the games, the 200 hours or so that I spent playing with friends and my brother were the most entertaining, and the most enjoyable that I remember.
K
