Autosurfs, they might give you traffic but it might not be that effective if you are looking for people to look or visit your site as most people would probably be only surfing for credits (say it with me-- LIKE YOU ARE!!). 

Overall I think at manual surf/traffic exchange sites are most effective in terms of getting people to visit your site, that is IT!!

One thing that I like about auto surfs though is if you sign up for one AND INVEST in one, then you can make money, because autosurfs usually have a tendencey to last (a little) longer than hyips do, they can actually be safer.

I currently have NO autosurfs in my portfolio, however, and take it from an expert, don't sign up for any. ;) (Unless I create one someday, LOL.)

Have a great day! -Edward Brown