To be honest, for the forum to be friendly to you or not it all depends on the activities you engage yourself in the forum. I can't promise you that if you go about cheating, spamming, and going against the forum rules moderators and sovereign members will take it seriously. You will be given the same penalty given to others who have done such here in the forum. On the other hand, if you adhere to all and make positive, engaging dialogues in the community then the forum will be more friendly than you have ever expected it to be.
Questions: and/or would you be really comfortable telling close friends (offline, in the real world) that they should come here and sign up?
No, my identity is very important to me. I don't think I share my identity in the forum with anyone around me not even my siblings. I can introduce the forum to them but they won't know how I exist in the forum. The reason is to avoid complications and informal behaviors that may affect your account here. If you don't complicate yourself in something, someone who knows you here can implicate you. With time you will understand.