Have a look at the best spinner.. but you should really concentrate on providing good quality content for your readers..
if possible do not depend on any tool to spin your article as rather spinning an article,it is good to develop ur fresh content everytime.
Spun articles are never a great idea in my opinion. Considering Google takes grammar, spelling, and paragraph structure into consideration when delivering relevant results, spun articles don't compare to human-written content.
yes you're right but spun articles are time consumer. i am not just saying copy and paste into some spinner tool. but better way is after spinning take a fast look at the grammer and correct them.
Go to a library with a voice recorder, or better still, a mobile or PDA with voice > text capability. Read some books on your subject matter. Rephrase what you're reading, sentence by sentence, and record it.