Part of it is where you use the device rather than how. This morning, I was quite happy to be able to use my phone to VPN to the office and SSH to a server to check out why someone else was having problems on the VPN... while still lying down in bed. Right now, I am happy to be able to type this on my tablet while taking a dump. Had the tablet been bedside this morning, it would have been much easier and faster to use it to check server logs. But, the laptop would be less useful lying in bed.
I have a few great apps that make fantastic use of the tablet, and I am always happy to have access to them. I much prefer going to meetings with a man-purse than a laptop bag, so I take a little performance hit on taking notes. The cellular access makes up for it though, as I can access the samba server and bring up documents remotely to display in the meeting.
At home, I only reach for my laptop if I need word, excel, or sketchup. My wife in contrast usually "works" from her desk, so she is more comfortable with the laptop, even when on the couch.