Neither - just build a diversified passive portfolio and rebalance once a year.
I think the OP has made clear he/she wants to investigate individual stocks, so you're probably replying to the wrong thread.
To the original question, I've used both but prefer Morningstar. I like the additional commentary/thesis they give for each stock, plus they provide similar (and perhaps better) historical data on stocks. Either way, just find a system you like and stick with it.