"Want the smallest most portable device you can get away with? "
"Want to be always connected to the Internet? Sure you do;"
"Just try opening a laptop on a crowded subway train or bus."
Someone needs to stop trying to arrange their life around their tech and try it the other way around.
If you are so overloaded with work, or so keen at your work, or so behind in your work, that you need to open your laptop on the train and start tapping away then some part of your work-life balance is in serious need of adjustment.
If you're THAT valuable to yourself or the business that you MUST be hunched in front of the keyboard, or online, every waking moment then why are you on a train? Your value/benefit demands that you be driven everywhere so you can work in the back of the vehicle and that you have a PA to handle messaging. Right?
I am an IT Manager for a high-tech company. Here's my solution, based on my personal values and my value/responsibility/benefit to the business:
Samsung Galaxy Note
It's a stupidly-big phone AND a moderately-sized tablet. I can keep in touch with emails, speak to people(!), do video calls and Skype/VoIP, check messages and do remote support via RDP/VNC/SSH/OpenVPN if there's a serious crisis when I'm on the move. If needed (rare), I can use the phone for reading/editing documents and PDFs, minor coding work and, if I really want to fill another pocket, it will work with a bluetooth (or miniature USB wired) keyboard.
Acer Aspire 5735 laptop.
It's a dual-core, 15.6" screen model, about three years old. The laptop comes with me very occasionally when I need it for a meeting or if I need to hook up to some kit when I'm on site. As it happens, the Galaxy Note has an MHL (HDMI) video connector and so I can use it for meeting presentations anyway. Laptop for use on a train? Maybe - on the extremely rare occasion that I need to type up a report on the way back home as it's needed first thing the next day. Typing stuff on the way TO work or site? That was done in the office the day before, or maybe at home if things get sprung on me at very short notice. If I don't grab the laptop, an original Acer Aspire One AA150 netbook comes with me.
In a nutshell, I have boiled down my tech-demanding activities to:
Desk-based: Use a conventional PC, or my laptop, or my phone (for calls and simple networking diagnostics)
On the move: Phone for about 95% of the time. Take laptop or netbook if needed.
Considering that the phone is always with me, that means I'm automatically setup for almost all my work and personal tech needs all the time.
Would I consider buying a UX31A or similar ultrabook (or a tablet for that matter) - sure, if cost/benefit was not an issue, but the device would probably spend most of its life on a desk, and all the things that make it what it is (size, lightness etc.) would be wasted - unless of course, I turned things on their head and altered my work/lifestyle to fit around the technology - mind you, that would mean taking the train to work instead of driving - and, no, I don't have a chauffeur!