I just found out that Sketchbook Ink finally added pen pressure support in the latest update, so I decided to give it a try.
I've always been interested in trying out 'Ink', because it's vector based app, which mean that you can output to very high resolution to be used for print. The biggest resolution it could output to is at 8000px X 12800px!! that's more than I would ever need for anything. That would solve one of the biggest tablet problem when it comes to professional usage, that is you can't really create something big enough to be printed.
I think 'Ink' still a long way from being something great. There's a slight irritating lag, and even more irritating pause when you undo, redo, zoom in and out, or happened to rotate the screen. The tools are too simple, lack of any kind of control or customization, and they plain need to show on-screen brush size! You adjust the brush size by pulling on this slider, but you can't tell how big it is on screen, you have to actually try it on the screen to make sure it's the size you wanted to use, if you guessed the wrong size of brush that you wanted, there's that annoying artwork refreshing pause that I was talking about earlier when you try to do an undo. It could get VERY annoying very quick.