ray,
How much of a hindrance is it in your experience?
No personal experience, really. But you get to a point where you understand enough about women to know that their reputation is more important than anything else, and doing anything to jeopardize their reputation is immediately going to close them off to you.
Your last situation was pretty much a deal-breaker because the two girls knew each other from sororities -- that was a pretty much a death sentence to your seduction. As a matter of fact, she was probably already worried about the fact that she came home with you and that your roommate saw you two; that's enough for rumors to start spreading about why she was there and what her intentions were.
If the assumption is that the two girls don't know each other, it's probably a lot less likely to be a death knell, but it still isn't going to bode well for her. Imagine if she does sleep with you and then wants to see you again; she has to come over to your apartment and see your roommate who is now
definitely going to be judging her to a certain degree. She won't really know your roommate, so she'll assume the worst before she assumes the best (the best case scenario being that your roommate doesn't care at all, but she won't necessarily know that for sure).
If you're already planning to move in with two other girls, then you can feel free to experiment with what can work for you. Sometimes you end up with roommates who have completely different schedules from you, and that allows you to bring girls home when they aren't there.
Once you sleep with a new girl, it probably won't become a huge issue for her to come back over. If she likes you and the sex was good, I don't think having female roommates will stop her from coming back unless she somehow knows them directly or indirectly. But getting the girl into bed the first time could prove difficult if she meets your roommates before that happens.
- Franco