If you understand the stuff, it can work wonders...if you don't, it will create a big mess. The surface tension of the stuff requires you spread it to wet the surface of interest, otherwise, it will act sort of like water on a newly waxed car. Once all surfaces are wetted, and you have a deep enough layer, it will self-level on its own with no further action. Also, people often try to use it too thin, or work it like concrete. While they all say you can feather it out, it takes some skill to do that. Flood an area with a thick enough layer, and it works great. Depending on the forumula, the temperature, and the substrate, it can start to set up in less than 10-minutes...you have to work fast. Anything you try to do after that starts is a disaster waiting to happen. Also, it is imperative to use the primer and cover it within the prescribed timeframe, or the bond will be suspect as well.
There's a good thread on this subject at www.johnbridge.com in their "Liberry" (sic) done by a guy who has been in the industry for decades...a good reference. I've only used it once, and it did exactly what I needed and wanted. Slick stuff, but expensive.