If this is going to be your primary device then I would avoid a tablet altogether. To me tablets are nice consumption devices meaning reading, playing simple games, watching a movie, surfing the net in a pinch. Yes, there are productivity software, but it's just too limited of a device in my opinion for any serious work. I have a Nexus 7 which I use mostly for reading, playing pinball from time to time, and watching a few movies. I surf the net with it from time to time, but nothing major since the screen is larger than my cellphone.
From my little understanding of Chromebooks everything is more or less stored in the cloud. That means you need to have an internet connection in order to do any work. If you are in a location with no such free service. Then you have a problem. You can get a mobile modem like Clear Spot, but it probably costs $50 for the device and then $50 per month for service which works out to $600 per year so that you can be mostly guaranteed to get access to the cloud; unless you are in a dead zone.
That leaves a netbook or laptop (Ultrabook). Netbooks are generally small, somewhat light, and inexpensive, but they don't pack much punch. Sure you can get by with a netbook, but they usually come with small screens and small keyboards which may or may not work for you. You should go to a store and play around with a few to test them out.
Laptops are generally the most power mobile device you have listed. But they can also be somewhat heavy as well. They weight on average about 5lbs - 6lbs. If you have a 5lbs weight at home just carry around with you at home to get set a feel for a laptop that is approximately that weight Ultrabooks weighs in at less than 5lbs and are basically 14" or 13.3"; some may 15.6". Laptops in general can give you a good amount of portability and power, but you should also consider battery life if you are no going to be near an A/C outlet or car most of the day.
Some laptops to consider:
Lenovo Yoga - Laptop / tablet combo, the keyboard folds back behind the display. In this configuration the keyboard is deactivated, but the keys are still exposed on the "underside of the tablet".
http://shop.lenovo.com/us/en/landingpage/yoga/?iPromoID...
Lenovo ThinkPad X series with laptops / untrabooks ranging between 12.5" to 14"
http://shop.lenovo.com/us/en/laptops/thinkpad/x-series/
ThinkPad Helix - 11.6" laptop / tablet. The screen detaches from the keyboard. Small and expensive. Weighs in at less than 4lbs.
http://shop.lenovo.com/us/en/tablets/thinkpad/thinkpad-...
Asus 13.3" Transformer Book TX300C - The Transformer series started out as an Android device which was a tablet with an optional attachable keyboard. It has now moved up into the laptop space. Starting price is $1,500 so it is not cheap.
http://www.pcmag.com/article2/0,2817,2420385,00.asp
Asus Transformer Book T100 (just announced today) - The little brother to the above TX300C. This is actually a netbook not a laptop with a 10.1" screen and a $349 price. It uses an Intel Atom (Bay Trail generation) CPU. It runs Windows 8.1. I think I would prefer this to the Surface 2 running Windows RT which cannot run standard Windows software like Windows Office XP, 2007, 2010, 2013.
http://reviews.cnet.com/tablets/asus-transformer-book-t...
Lastly, are you getting bored during a sales meeting or whatever words your client is yapping away at you simply going in one ear and then out the other? Fear not!!! Simply whip out this 17.3" 9.90lbs monstrosity and start having fun by killing people (virtually speaking... yes unfortunately killing people in real life is a crime... if Congress could only pass an Amendment to change that...). That's right!! Just load up games like Crysis 3, Battlefield 3, Far Cry 3 (what the hell is this fascination with the number "3"???), Hitman:Absolution, and Skyrim. Freak out your co-workers and learn how mod characters in the games so that you can replace the default faces with your co-workers faces and start killing them!!!
http://www.xoticpc.com/asus-g750jxrb71-backorder-p-5969...
Anyway, that should give you a starting point for your research.