Yesterday, February 1, there were 27416 sites viewed at Hit Bandit - this is fairly typical for a Friday. Mondays and Thursdays get the most surfing due to the 20% extra surfing bonus - without the bonus these were always the weakest surf days and that is why the extra bonus is available on those two days.
Upgraded members are getting maximum around 250* hits per day to their sites, free members around 120* hits per day - if they have enough credits assigned. The difference is due to the priority that upgraded members get when showing sites. For example, if someone surfs 150 sites on one day they will see all of the upgraded members' sites, but only about half of the free members' sites.
Furthermore, free members who don't login for several days will get a lower priority on their sites (if they still have credits assigned) until they log back in. So for best results, upgrade, and if you can't afford an upgrade, login at least twice a week!
*Figures apply to non geo-targetted sites, geo-targetted sites will get less hits.