I just started to do Epoll in September. I got a survey worth a lot and was able to cash out in October for a $5 Target gift card. I them cashed out in January. Again, got a $5 Target gc.
I just got the October gift card yesterday. God only knows when I will get the January gift card. Epoll sent out a msg saying they were really far behind. I do the polls when they are added to their site. From my own experience, they are a slow earner. I have only gotten one large point survey and that was for the October cashout. Since then, nothing except the polls on their site. I do know you can get 200 points every quarter for updating your profile.
So, all in all - nothing great. Easy to do. I'll keep at it.