This is easily one of the best games I've ever played. It's a game with a lot to do and a lot of depth to the story. Every character is well written and fleshed-out, and it takes a lot of time to get to know them as individuals. The story develops as you interact with other characters and help them out, and there's a lot of suprises to be had.
Probably the most interesting feature of this game is its genre - it's a farming simulator with RPG elements. I know this sounds like a bizarre combination, and it is, but it really works! You start with minimal supplies, and have to work with your farm in order to make money, upgrade equipment, buy weapons, etc. It feels really rewarding and satisfying to build up a great farm and explore new areas.
This game also allows you to tame the monsters you fight, and they can help out on your farm and produce materials like eggs, wool, claws etc which can be used for cooking or crafting respectively. There is an absolute ton of stuff to do in this game, and I guarantee you will never get bored.
The RPG parts of the game are challenging without being frustrating, although I sometimes found areas where you had to keep fighting monsters to get certain items a little tedious due to poor drop rates, but fighting monsters can also get you rare items, so it's not a complete loss of time.
The controls are also very fluent - I found the controls of Harvest Moon: Island of Happiness very awkward due to being almost entirely stylus-based, but RF3 gives you the option of both touch and button controls, and both are perfectly responsive and easy to learn. My only minor complaint is that sometimes using the quick-select menu can be a tiny fiddly, especially when switching items around, but that might just be me.
All in all, this is an incredibly enjoyable game that you will never forget. There's a lot to keep you occupied and the story is very compelling. If Amazon allowed higher star ratings, I would still rate this game one star higher than the maximum allowed!
Just be warned - you may forget to eat or sleep for a while!