Lightspeed Panel

Reward System: Points, worth approximately 100-115 points/$, that you can redeem for Paypal payments, gift cards, or other merchandise. Surveys also reward a $5000 sweepstakes entry
Minimum Payout: 60 points for a song download. $5 certificates start at 550 points.
Frequency/Length of surveys: A little over one survey per week, the length and points vary greatly. I've gotten as few as 50, and as many as 500 points for a survey. Average length is probably 20 minutes.
Summary: Great experience so far, very prompt payment! They were the first company I received payment from. I have received a few invitations that I did not qualify for; however, I have qualified for about 75% of the surveys I was invited to. Make sure to fill out all your "profiles" and "quick matches" that help them match you to surveys. Unfortunately, they are not always recruiting. If you see one of their banner or ads about recruiting panelists, make sure you take the opportunity.
Recommendation: No reason not to sign up for this panel, if you get the chance. Lightspeed Website

I have earned: 775 points after about 3 weeks
Requested: 575 points for a $5 Paypal payment
Received: $5 after one business day, shown below

(perks.com is the rewards company that redeems Lightspeed points)