Until I bothered to find out how to use it properly I would have agreed with that comment but when used correctly it's a very good and effective product, if you use too much and/or don't work the product properly it can dust but the newer version is even better.

At the moment I use the following :-

Snow foam - Autobrite Magifoam
Tar remover - Autosmart Tardis
Shampoo - Dodo Juice Born to be Mild or Sour Power
Clay - Bilt Hamber medium grade Autoclay
Polish - Autoglym Super Resin Polish
Wax/Sealer Dodo Juice Supernatural Hybrid
External trim - Chemical Guys New Look Trim Gel
Glass - Autoglym Fast Glass, Autoglym Glass Polish and Gtechniq G5
Interior Trim - Autosmart Dash Dandy
Under bonnet plastics - Autoglym Vinyl and Rubber care
Carpets and Upholstery - Autosmart Brisk
Tyres - Autoglym Instant tyre dressing
Wheels - Wolf Chemicals Nano rim sealant

If you're going to clay your car then I really recommend you get a good tar remover, if not you could spend far too long removing the tar through flaying which is a ineffective and inefficient way of doing it !

If you do decide to clay the car you will either need to use it with a clay lube or if you buy Bilt Hamber clay just tap water. I cut my bar into 50 gram pieces, they're a good size and if you drop a piece on the floor you'll have spare pieces ! I flatten the clay to about 5 - 10 mm thick wich is thick enough to hold any imbedded contaminants that may come off the paint. Once the car is clean and de tarred I start to clay.

Rather than go on and on about how I clay here's a guide.