Mintvine is a great survey site, although it also has polls, offer walls & other ways to earn. They send surveys very regularly (several times a day), so it’s easy to rack up points. Like most survey sites, you need to spend a short amount of time filling out your profile. This means that you will get sent relevant surveys & get screened out less frequently.
The plus points of this site are that it’s really easy to use, surveys are frequent, always credit & you can cash out via a variety of methods. I am currently receiving the cash via Paypal. But you can opt to receive a gift card from; Amazon, Debenhams, House of Fraser, iTunes, New Look, Pizza Express, Tesco, Starbucks & lots more! They also pay a small number of points even if you are disqualified.
The only real downsides of this site are that they keep you waiting for at least a week whilst your points are approved & that they pay in US dollars, so you need to convert the currency which means you lose a bit.
This site is a great little earner & I highly recommend it.