Obviously it has had the effect on the stock market that was desired. However, it has not helped unemployment. It is not getting the banks to lend more. Corporations are still hoarding cash etc...
It isn't a question of 'chicken little', it is a question of learning from past mistakes.
We have added over $5 Trillion to our nations debt in the past four years and $10T+ in the past 12. In addition, the Fed has added about $2.2T+ to its balance sheet by printing money and buying bonds. This is a very dangerous game. Could it end up working out in the long term... maybe, but the downside risk is greater than the upside potential. Especially if the banks stay with the higher credit standards (as they should).