Yes, the difference between the trade and retail paints is quite substantial. firstly the stuff you get at your well known diy centres (retail) is made to be used as is. It is not as concentrated as the trade paints, which are made almost twice as thick, in order for it to be thinned down. Trade paint is not made to be used neat, you will get problems with patchiness, and skidding if you try to do so. secondly, if you look at the coverage on a retail can, in comparison to a trade can, you will find you get almost a 3rd more coverage on the trade paint. this is because, as it is thicker paint the opacity is much better, therefore giving you more coverage, with use of less paint. So even tho you may find that trade paints seem more expensive, in actual fact they prob work out about the same as retail.