I’ll give you my advice on both friends and “Real” actors.
I filmed a short (7.5 minutes) film a month or so ago. I used only friends. I had 6 people total, only 3 had a lot of dialogue. I used people I thought had the personality to act. My lead actor is real outgoing and friendly, however when put in front of the camera, he tensed up and become very self conscious and mundane sounding. It worked out alright for the character, but it made for a lot more takes than I wanted. I ended up casting the other people very well and they did great! However, 2 of the characters had a really long dialogue scene together, and I wanted them to memorize it all, gave them a lot of notice, and reminded them a lot. However, they didn’t have much memorized when they got to the sset. So, it added at least an hour to the shoot, we had A LOT OF TAKES. Also, the biggest thing was that on multiple times, they’d tell me to do something a certain way or offer way too many suggestions slowing stuff down. Also, trying to change lines and whatnot. The biggest problem overall though, was that my best friend played one of the characters. He was great, but he acted like he was co-director or something like that. He also, kept making fun of me, as though we were just hanging out like normal, saying crap like you suck at directing, this line sucks, etc. I know he was just razzin me, but that is not cool at all. It made it a little less enjoyable for me.
Now, the thing about “real” actors. I’m not sure how “real” your actors are, or what your resources are. But at the university I attend, we have access to actors through the theatre department. Some are really good, and some are pretentious a-holes. I’ve heard a lot of horror stories of actors quitting halfway through a shoot. Like after a week or something. Therefore, take into consideration how long your shoot will be. If it’s gonna be multiple days, make sure they are reliable or hold them to some kind of contract. Sometimes they can be a pain to work with. The older the better. Freshman and sophomore actors seem to be worse.
So, there it is. Sorry all that was so long. Hope everything works out for ya!