I like Neo Megilp so far, in fact I used it for a large sunflower painting (that's still drying). It makes the paint flow off the brush onto the canvas in a smooth way. Of course, if you use too much it sort of makes a slime. The downside is dry time. I'm used to Liquin, which dries overnight. But Neo Megilp won't dry for a couple of days.
Neo Megilp is a clear amber, thick, goeey substance that doesn't want to come out of the bottle when you turn it upside down (like ketchup). The label says it's a 21st century formulation of one of the Old Master's true secrets. I read somewhere that its "ecofriendly." I don't really know what that means because the label also says it contains petroleum distillate. If swallowed do not induce vomiting. Call physician immediately. Like anyone would drink the stuff?! But if you can imagine what the Old Master's formulas contained, stuff like black oil, mastic varnish, damar, linseed and other mysterious ingredients. There's a good description of these formulations in the book How to Paint Like the Old Masters, by Joseph Sheppard.
To use it I pour a little dab in a small wide dish. Then I dip my brush into it before I pick up some paint. So it mixes with the paint on my brush when I stroke it on the canvas.
I continue to be interested in painting techniques. Using Neo Megilp is another experience for me. You can read about some of the other mediums I've used in this post.
If anyone knows more about Neo Megilp feel free to post a comment.