This is a solid addition to the Harvest Moon series. It is similar, but not identical, to the PSX version 'Back to Nature' - there are enough new features to keep a veteran BTN player interested.
Harvest Moon games are obviously not for everyone. It can be repetitive and there is no shooting or violence. My interest in them lies in the nonlinearity and the juggling act you must perform between making money, upgrading your facilities, making and maintaining friends, and wooing your prospective mate. Given the real-time clock, you can't always get everything done in a day.
Finally, given the repetitiveness and potential length of a game, I feel that the Harvest Moon series is ideally suited for a portable console like the GBA. I've found that the key to enjoying a HM game is in patience and short little bursts of gameplay when you have the time.