Prime is good for all conditions - chlorine and chloramine. It detoxifies ammonia to ammonium (their claim). The Wardley stuff really just deals with chlorine. Not a problem for me as I only have chlorine so that is what I buy. It is important to check if you have chlorine in your tap water or chloramine (the water company will tell you, also ask if they plan on adding it in the future).
The downside to Prime--it smells awful! I know it's good value for the money but that sulphur odour is a turnoff. I use AquaPlus. It doesn't neutralize ammonia or nitrites, so I just stay on top of water changes...
They say you might experience that sulfur smell using Prime. I don't think I ever have. Prime is a new product for me (I started using it when I heard a lot of people talk about it.) So far I have no reason to change. In new water you can see it work immediately, if you test for ammonia. (Which I think it's probably really ammonium.)
I have had good luck with all of them Tetra, API, and Prime.
Oh, I figure I would mention this, I seen someoneon another board talking about having a little bit of one product left over (can't remember what brand, but it was a tap water conditioner), so he decided to just mix the rest in with his new product(different brand). A few days later he said that he opened it to find the worste smelling liquid he had ever seen. Just food for thought. No mixing different brands.