Mechanical Turk seems to be filled with people itching for some community to participate in -- why not get paid for it at the same time?
Even in Russia it's about the average income IIRC if you assume 40-hour workweek.
Getting honest feedback probably depends very heavily on survey design, instruction sets, and, if you've been doing it for a while, reputation.
With a jobs size this small you'll get information that might be useful, but will probably be biased. I wouldn't trust it - but I would use it as a starting place.
For the incredibly low price I think it's worth it.
Do MTurkers tell the truth though? Presumably one person can run a dozen fronts so that they can answer questions that require a specific demographic. Or they masquerade as elderly females to appear more trustworthy and shame you out of objecting if they've not done the job properly or whatever.