I bought both the Vitrea 160 (for glass) and the Porcelain 150 (obviously for porcelain) and worked with them this past weekend. Neither gave the kind of results that we might have imagine, but I do see some potential, none the less.
In both cases, the first issue is that it is nearly impossible to apply a smooth, consistent coat. Porcelain and glass are both so slick that it is hard to apply evenly. Look at the two "before" shots below and you can see what I mean.
[photo - porcelain before]
[photo - glass before]
The paints can be thinned, with water or with Pebeo's thinning solution. I tried water and in deed did get a very thin mixture that was more consistent, but not nearly solid enough for what I was trying to do. Playing more with the mixtures may have produced better results. I'll work with in the future.
I am also thinking that it may be possible to get a smooth and consistent application by using an airbrush. I plan to pick up a cheapy at the hobby shop just to try it.
The second issue was how to remove the paint once it has dried (but not cured/baked). You are supposed to wait 24 hours after painting before baking. I waited about 20 hours before doing anything with it. I was not able to remove the paint from the glass or porcelain using water or acetone. So I suspect that even if the "baking" with a laser would work, you would still have issues removing the undesired part.
I thought that, given the difficulty of removing unused paint, it might be useful to remove the undesired paint with the laser and leave the rest to be baked in the oven the way it was intended. I ran tests on both the porcelain and glass. On the porcelain, you can see that I each test either removed too little or too much. The best one (as far as paint removal) removed the glossy service of the tile as well.
[photo - porcelain after]
On the glass, however, I got some interesting results. In the photo, you can see that it removed the paint nicely and provided a very nice frost to the underlying glass. I think this could have some applications - frosted glass with various colors of design/wording. (note - I did this rounded glass without the rotary attachment - waiting for it to arrive for testing)
[photo - glass after]
All in all, I am not thrilled with any of it, except possibly for the reverse etching on the glass and baking the remaining paint. The effect of the light coming through the glass and paint is very nice. I will continue to play with this, as I still have the paints. Maybe the airbrush combined with negative engraving will be usable, but time to paint, time to dry, time to etch, and time to bake adds up to a lot of time - not sure if the public's perceived "value" will bear the cost of the time.