The last few weeks I have been playing around with GW's new paint line, and I am rather impressed. I think that the new line is far and away the best gw has done so far.
The new pots are great, the lid locks open, the inner lip of the pot is shaped to prevent spilling, and the inner tab in the lid is sloped so that it holds just enough paint.
The paint itself is great. it flows from the brush well, without glooping on your model. My favourites right now are the shades and glazes, which are great for getting a particular color or texture effect you want.
All in all, they are a vast improvement on gw's previous paint lines.