Iv used a Docking Computer since i could afford one in Day 2. For me it lands far quicker than i ever can & it seems to reduce the 'permission denied' messages in crowded outposts.
NEVER EVER EVER leave it unattended when docking, it isn't 100% reliable. Pre 1.2 launch it failed me once & i had to abort (that's from 1000's of landings), but since 1.2 launch about 3 times now it's gone through a slot & decided to try to go back out through the station wall.
I always watch EVERY time just in case, but as i say, if you're not good at landing then use one, it's quicker.