It is always a good idea to have options!
We use Serial from the Mac OSX app store which is a paid app. It works really well and is easy to use, almost install and go. However, we realize that since is does cost money, maybe people want to try something else.
Go here to see a collection of Mac Serial terminals. We have not tried them all but there are options here for people who do not want to buy Serial.
We do not offer support on these but we will help you get set up. There are other articles on how to see the gStrength on your mac which are here.