first off its a pain in the ass to do multiple orders or orders only at a certain time of day. If you want to sell the whole portfolio it takes about 30 minutes of work each time. Mind you this is based on my experience from a year ago. Perhaps it has evolved to basket trading, I cannot say. In general sites like stockpickr.com are alot more user friendly and interactive than collective2. Mind you stockpickr does not give annual returns or sharpe ratios on portfolios at this time.
If you are simply trading an index and generating signals, then collective2 may be for you. Otherwise, don't bother. This is why so many ditch their systems because its a waste of time inputting stocks.