I have an adjustable stem on one of my road bikes. (It is black BTW). I got it at Performance a few years ago. I've ridden many a mile with it and haven't had any problems.

Now that I am back on the bike (broken humerus-8 months ago)I decided that the angle of the stem was down too low and therefore I was putting too much pressure on my stiff arm. So we adjusted it up which feels much better. We marked the new spot with a piece of red tape so we know where it is now in case I want to change it again. This procedure took all of 5 minutes to do which is why I like this option.

One of the reasons I put an adjustable stem on in the first place was to see if it would make a difference climbing as we have a lot of hills around here. I haven't changed back so I'd say for now, I'm glad I did it.