The main difference between quantitative analysis and technical analysis is, that quants are not focused on what the market will do in the future, but they will try to develop a trading – investing strategy which can be quantified.
Quantitative analysts will not say “this candles stick pattern predicts a bullish move” or “the trendline break will lead to a bear market”, but they might use a candlestick pattern or a statistical trend definition to run a statistical test if it has got any significant edge and then design a hopefully profitable trading strategy.
A trading strategy consists of an entry, an exit and a position sizing algorithm. Thus quantitative analysis can give you the expected risk, the expected return, the Sharpe ratio and other key statistical numbers to describe the outcome of a specific entry-exit-position sizing algorithm.
3A technical analyst might say that that slow stochastic is oversold and thus it might be a good time to buy, or he might say that the fast stochastic is overbought and thus it is good to sell.
He might say that the market is trading below the golden cross and thus it is a good time to be bearish. Or he is hoping for a retracement to the nearest Fibonacci level an thus be bullish. It all depends on his preconceived opinion, not on what the indicators tell.
A quantitative analyst might also use stochastic and moving averages, but most probably won’t care at all where the market might head tomorrow. He will have a statistical backtest of his strategy, giving him performance and risk figures. And he will let the strategy trade as long as these figures are met in real-time.
In the end, both methods have limitations. You do not need to pick one. Knowing basics about both will certainly give an advantage.