witch one goes better with big community vbulletin or ipb (invision). Forum would be integrated to site witch has about 20K users online everyday.
If you have a IPB with over 50,000 members,then it lags a bit Slows down and take time while loading But vbulletin isn't effected by members,it works the same with 1 member or 1 lakh members
A bit of doubt about this statement. I have more than 1,50,000 members in IPB and working fine. Moreover, IPB latest version improved in performance for big boards. I suggest to go with vBulletin as most big communities I have seen so far are of vBulletin. Moreover, the latest vBulletin 3.7 (yet to be released shortly) is outstanding in features. Any other forum cannot be compared with that.