It depends on what you do with it. In general, it’s a plus – especially if you can write so fast that it doesn’t interrupt your thoughts. Typing shouldn’t be an obstacle in between one’s thoughts and the medium. It really annoyed me when I started to learn the Colemak layout, since I noticed that it slowed down my thinking because I got too distracted by the typing process itself. It improved after a while, but it still gets in the way, so unless you have a good reason for changing your default keyboard layout, I’d recommend sticking to the first layout you learned and slowly improving on your typing speed.

Btw, I should add that the faster you type on a real keyboard, the more annoying it feels to type on a virtual keyboard, but then again I guess most people wouldn’t type longer text on a virtual keyboard anyway.