There's no catch. I use it everyday. The only thing I wish it had was more Batch Edit options (like saving a sequence of edits and then applying them all to selected photos, rather than just black and white, or just sepia).
The program can be a bit buggy. Sometimes it won't automatically import new photos and when I browse to them and select them to be imported, nothing happens. Other times it will select a photo and then I can't click anything and it won't let me deselect the photo. But hey, it's free and does almost everything I use, so I can live with the bugs.