I have followed for a few month a simple strategy outlined here: Trading System and it seems to be working quite well.
This is not a holly grail by any means, but it does way better than many strategies I've tested!

Unfortunately the NDQ signal didn't trigger on their web site but a few days late and I had some stocks from that index that tumbled quite bad.

For a free site the info contained is not bad at all..but I wish to have more backtest dates for their signal.