Think Surveyhawk was probably the best online survey site I tested (at the moment). Nicely designed with a good choice of surveys.
Their database includes 450+ companies that are looking for people to participate in surveys. Has a good selection of surveys for UK residents which can't be said for some online survey databases.
The first I will say is I liked this website the first time I visited. Being a trained graphic designer I always appreciate nice design and this website had the best design out of all the sites I tested. They have a large number of surveys. Probably one of the largest databases out of any I reviewed. Probably not as good bonuses as some which a slight black mark.
Survey Scout is the longest established paid survey website. So is the original the best? I wouldn't say it was the best but at the time of writing it is in my top two or three.
Unlike other sites and products that pay you for taking surveys, it actually allows you to take a sample survey so that you can see if this is the opportunity for you.
Paid Surveys Etc is one of the new kids on the block so to speak in the world of paid surveys. So does it live up to the hype? Well I would say yes, as long as you are realistic and don't expect to be earning £5000 a week.