I use the recipe analyzer a lot. I DO believe it is accurate. You can click on any ingredient and see the details. It does help to put in a specific brand of something if you have it. The database is quite extensive.
That being said, sometimes you have to use common sense and tweak it a bit. For instance, there are several versions of Splenda and it doesn't always get the right one when I enter it. I know my Splenda is zero calories, so I just leave it off the list.
But, I LOVE the nutritional breakdown - I try to balance my calories 40/30/30 and this really helps me make sure I am getting enough protein and fat and not too many carbs