Vallejo Game Colour Thinner

I've been trying out this product on a couple of recent miniatures.

Previously I'd thin with water, but that will change the density of the colour. This thinner claims to thin without loosing opacity of the colour (it says so on the bottle). After trying it out, it certainly does do this well, retaining the intensity of the colour. However, an unexpected side effect is that the paint then goes on with a shiny, satin finish which may or may not be what you were looking for. All in all, it's good at what it does, but I'm really only going to be using it for certain things that I don't mind ending up a bit shiny. The shine may disappear of course if you matt varnish the miniature, so this may be a non-issue, but most of my minis just sit on a shelf and don't ever leave the room they were painted in so I don't normally bother with varnishing.