I had properly disabled the stock app and did everything properly when installing Handcent and STILL got double/triple messages more often than not with Handcent, as did my wife and a few buddies of mine. In fact, nobody that I knew personally had a positive experience with that app and that includes me using it for about six months. I uninstalled it on my Droid, my wifes and even suggested to my buddies that they do the same. Every single one of us has had a substantial decrease in double messages since. Sure it still happens from time to time with the stock app but nowhere near as frequent as Handcent. I tried contacting the developers numerous times and they seem to be more concerned with fancy colors and images more than stability of their app. You can do what you want but I've been happy with deciding to do away with it and my only regret is not uninstalling it sooner.