"it’s actually really fast and responsive"

Is everyone today equipped with at least 4-core 3GHz i7s or what?

Text Edit demo is barely responsive on my Athlon 64 X2 4600+ in recent Google Chrome beta (25.0.1364.84) on up-to-date debian wheezy. To the point it's unusable, unfortunately.

I admire the project, it must have been a great fun to build it and it is impressive achievement. Really!

I still hope it may be optimized more, so it will be truly responsive. Even then it doesn't mean it's the right way to go. Web developers, please, do not write your websites as Qt apps to compile them later with emscripten-qt!