In general I use the computer from a fixed place of my house, but I recognize the comfort of the cell phone when the activity that I am doing allows me to do it
On the tablet is very inconvenient to play multiple tables at once. Sometimes I play through the tablet on pokerstars. I like to play through the computer.
playing on desktop giving me more room to do other activities. However playing it over my phone does help me on maintaining my attitude & disciplines, since I have to focus on just one thing and being tilt there sucks too.
I personally like to play with a large monitor - can be conveniently positioned a few tables. in the absence of access to a computer and sometimes you can play on your phone