I'm currently replaying this game for the third time, and I find it as addictive and enjoyable as the first time I played it. The basic gameplay consists of going into dungeons with a couple friends to fight and collect ingredients, and then synthesizing items in your workshop from those ingredients. Item synthesis is occasionally tedious but can be also be fun, especially when you're making ingots/cloth for weapons and armor.
I think the main strength of the game is that the characters and their interactions are very amusing, and since there are many different endings, there's lots of replay value. (The first time I played it, I did so without the walkthrough so that works perfectly well if you just want to enjoy the game at your own pace.)
I would say if you're a fan of Rune Factory (and maybe even Harvest Moon), you'd probably like this game too. The only annoying thing I can think of about the game is that you can't select all ingredients when you're moving stuff - this means rapidly clicking through dozens of items to sell them or transfer them. You get used to it, but I do hope the other games in the series fixed that. Well, my first hope is that they bring the other titles to the US... a "select all" button is secondary.