I would say on my own well protected car it didn't work all that bad. Very little tar and iron deposits so I think it has its place. There is only ever minor iron removed with both combined and stand alone iron removers. Tar removers help remove organic fallout such as tree sap and honey dew / aphid droppings so a tar remover is a lot more important to me. But if the car is well maintained and protected hopefully this shouldn't be bonding and only require a basic hit with a tar remover to get rid.
If you are reguarly changing LSP's before they start to wear off then this might be a suitable choice. but as said stand alone products work better.
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RyG was it not any good over the CQ?
Did you get rid of the water marks?