word choice - Difference between ”conditional” いい and 方がいい for providing recommendations

I've noticed that there are multiple ways of providing or asking for a recommendation in Japanese.

The sentence structures I'm talking about are as follows:

したらいい
すればいい
したほうがいい

In almost all situations I see these they get translated as "should do" and they all seem to share a common structure of equating the done action as being "good" but is there a difference in nuance or are they interchangeable?