I think the QQQ's are a difficult trade also. Frankly, I think all indexes are a difficult trade. I haven't been able to make money on them consistently. Every so often you get a high probabilty set up (like the gap up this past Friday). When you've traded the thing long enough those set ups will just call you on and you'll have to trade them. And if you can exclude your trading activity to only those high probability set ups then the QQQ's and SPY are great due to the liquidity (you can really pile it on size wise) and downtick rule exemption.
But among my peers who are successfull filter traders, none of us have been able to make consistent money trading the indexes. A few of us have been stubbornly tryin to "figure" them out, but having used up allot of mental and financial capital we all finally reached the same conclusion. Indexes are a tough trade.
If you are going to trade them I think you need allot of patience as well as the experience to recognize the high probability set ups, few of which are the standard patterns you'll find in a typical book on TA.