Opinion Outpost is best of all, free to join. They use profiles of your information to match you with possible surveys, which you get paid for.
-Very professional site. It is easy to navigate and looks good.
-Low minimum payout ($5).
-Pays more than most sites similar to it (Cashcrate, etc.)
-Referral program (though it is only a one-time reward-I like this because it keeps people form spamming their links everywhere)
-Great support system with fast responses to queries- they respond by email-the one time I used them I was very happy with the response.
-It takes a while to be matched with surveys (a few weeks before they really start to roll in)
-You might not get opportunities every day, though you get more as time goes on
-You might not qualify for a survey opportunity
-Sometimes it takes a long time to do a survey, even the ones that don’t pay alot. Pay is not always commensurate with the length
-Pay only by check or Amazon gift card (no Paypal)
Overall, Opinion Outpost is easy to use and pays well (usually $1.50-$2.50 per survey), though it can get pretty annoying sometimes when you are trying to qualify for one and you just can’t get in. The profiles you fill out in the beginning are optional but necessary, and really long. I find the surveys pretty interesting, albeit repetitive. They also have a referral system which gives the referrer 20 opinion points ($2) for each referral (one-time reward). If you want to sign up under my referral code here is the link: Opinion Outpost.