As far as I know, most of Pencil developers are on Linux so Pencil is literally developed and tested on Linux most of the time.

Today, Pencil reached the #1 spot on both of GitHub trending lists (repositories http://i.imgur.com/4SRsna1.png and developers http://i.imgur.com/JrqTy3k.png).

I can understand that you had some issues with Pencil on Linux but claiming that Pencil is very unstable on Linux is a bit uninformed given its validated quality.

What's your point?

Native versus web app.

Calling a compiled Flash app "native" is a bit of a stretch.

You can compile JS (or pretty much any other language, really) to native code with sufficient effort. I'm not sure that alone is sufficient.

Head over to their GitHub page and post your issue. They're pretty responsive.

I prefer to pay for a stable solution than spend my time on improving an unstable one. Funny, when I was younger it was the contrary.

What do you mean by unstable ? The electron version is very smooth on linux. The XUL version was quite slow. Electron version uses less resources .