IMHO, that (even within the MAJOR OVERHAUL they've been having lately) it would be MyPoints (5 disqualifications cap / day for 25 MyP's or slightly > 15 cents, each disqual lasting < 2 minutes, sometimes < 1). The only completed survey that had me unhappy on MyPoints was an Ipsos one (20-25 minutes for just 49 MyP's or close to 30 cents).

The most satisfying surveys are the WayPoint (pop unexpectedly) ones on eRewards. They always end for me with an error, but they always seem to credit them as fulfilled at the full 4-6 "dollars" (their currency) rate. No much waste of time...

PS: Because of my location (quite often the 00xxx US zipcode will disqualify me) my percentage of qualified surveys may be lower than some, even as sometimes I use one of my relatives' FL one...