So there are quite a few ways to give a recommendation in Japanese, depending on the nuance. For example, to say something like "you should buy ~" you could say:
買ったらいい
買えばいい
買うといい
買った方がいい
Looking at this conversation here:
A: 電子辞書を書いたんですけど、どこで買ったらいいですか。
B: ヨドバシカメラで買ったらいいです。
According to my teacher, the construction 買った方がいい would not be appropriate as the answer form, but all the other constructions would be fine. Does anyone know why? My text book actually treats the た方がいい construction as a different form, and lumps the other three together but I can't see what's different.
Also, I often ask friends 「どこへ行った方がいい?」 when asking where we should go (to have coffee etc). Considering the question, am I using the right construction here, or would one of the others be better?