Yeah, I use the autoexecute feature on a regular basis. It works well, but is not without some problems. Recently I've been using 4 stops per position (a technical stop, stop loss, break-even, and profit target) and when I'm holding several positions at once, I find this feature to be very useful.
As I said, it's not perfect. You can't set the computer and go to work and expect that everything will turn out ok. 99% of the time it'll be fine - but that one time could really screw you over.
The other day I entered a series of auto stops, but one stock wouldn't allow me to do it properly because of a bad data tick. The data available suggested that I'd already been stopped out, when in reality the stock never actually traded at that price (as far as I know).
Well, hope this helps.