I like Prime as well. Take care not to use things like "Stress Coat" or the like....things that contain aloe, which can clog the gills of your fish. I've not personally used this product, but have heard some really bad stories about them. From PERSONAL experience, Prime rocks!
The important ingredient in a water conditioner is sodium hydroxymethane sulfinate. It's in Tetra AquaSafe and it works well for me. I'm superstitious to some extent because I've had trouble when I've switched. It's probably not the brand but none of the other is going to work any better than AquaSafe so I'm going to stick with it.