I've been using cool-trade for about a year. The Cool-trade office happens to be located near my home, and I did drive over one day to meet the owner/developer and check things out. I allow C-T to run in the background which frees my mind for trading futures. Some observations:
C-T is extremely easy to use. No programming skill is required to use it effectively. That defines the intended audience, imho.
C-T strategies are mostly form-entered with help from selection menus. The user doesn't have access to a programming language, so it may not be possible to invent a new or arbitrary trading rule. On the other hand, it has a great deal of flexibility and can closely approximate most ideas. Also, the owner/developer has been very willing to add indicators that users request.
It's not very pretty, imho. Otoh, you aren't supposed to watch it, anyway.
There are some restrictions. Order size is always 100 shares or a multiple. It handles only stocks, not derivatives. It can only watch 40 stocks at a time. So if you're watching a thousand penny stocks for a breakout, it won't help you.
To sum it up, C-T is designed for people who want an automatic trader that is easy to use and cheap, and it meets that need quite well. For those who need a powerful programming language or need to scan many stocks in real time, it's not going to be sufficient.