I have not encountered any problems sharing between Win 7 Professional and Vista Home Premium or Win XPO Pro but I hve not done thorough testing yet. I have not had to tweak anything in Win 7 ... yet. Come to think of it, I'm not sure I have written anything to the Win 7 computer from the other LAN clients. I've been accessing the other clients without problems. I'll have to try writing something to the Win 7 PC from one of the others on the LAN.
It has been so long since I set up the file sharing on the various computers that I'm not sure but I don't think I used 'Simple File Sharing'. I don't remember why.