Excluding the 15 minutes I docked it when I first bought it, I have been 100% portable. If I ever get around to getting ring fit then I guess docked mode will increase in use, but until that point I doubt I'll bother since I haven't over the last 2.5 years.
Love it as a portable device, use it whenever I take the train to see the girlfriend, travel for work, lying in bed, while mindlessly half paying attention to a show on tv, etc. It's brilliant.