I picked a new machine for my job a couple of days ago, so this is still fresh on my mind. Keep in mind that this is from the perspective of the UK (US is generally MUCH cheaper, oftentimes machines cost 50% of what they do here).

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First, my criteria for the new machine are:

- Portable, screen size between 12" - 14", preferably as thin & light as possible

- SSD (No weird HDD/SDD hybrids)

- Reasonable resolution. 1080p here is overkill, 1366x768 leaves something to be desired

- No graphics card, I don't have a use for it, excess power usage & heat, another part that takes up space, adds weight, can break and needs driver support

- No optical drive (same reasons)

- Battery life 5+ hours

- Reliable brand. Good ones are Apple, ASUS, Samsung, Toshiba, Lenovo. Sony maybe but only with expensive models. Acer & HP are immediately disqualified. I really like Dell for some stuff (monitors, towers) but they seem to have a bad reputation for making reliable laptops.

- Good value for money. I really dislike over-spending even if it's not my own money

- Good Linux support

- Solid build quality

I don't care that much about performance. Sandy/Ivy Bridge is generally fine for me, and for the stuff that I care about (mainly reading/writing text) raw CPU power doesn't matter that much.

This filters things down quite a bit and brings us to the following models:

- Macbook Air 2011 (including this as it's a very similar machine to the 2012 but with apparently better Linux support)

- Macbook Air 2012

- ASUS Zenbook

- ASUS Zenbook Prime

- Lenovo X1 Carbon

- Samsung Series 9 900X3D

- Samsung Series 9 900X3C

- Lenovo X220

- Lenovo X230

Another requirement is dual external monitor support. Doing this on a laptop and under Linux turned out to be quite the tricky problem and the issue that probably consumed most of my time spent. For laptops with only 1 display out, there are 2 ways of working around this:

1. USB to HDMI adapter. Basically an external graphics card. This requires USB 3.0 for bandwidth reasons (USB 2.0 gives 35 MB/s. 1080p @ 32bpp is 8 MB / frame, meaning single-digit FPS rates at most) which disqualifies the MBA 2011 since it only has USB 2.0. Even with USB 3.0 from most of what I could find, these things are not really supported under Linux and probably best to avoid.

2. Matrox DualHead2Go. This is a cool invention that pretends it's a 3840x1080 display to the OS and then splits the signal digitally into 2. Costs about 120 GBP, but with not letting the OS know that it's actually 2 displays, also comes the OS not knowing that it's actually 2 displays: Fullscreen doesn't work properly for a lot of applications. And even though this could be made better through some window manager trickery, that feels like hacks, piled on top of more hacks. I also don't want to carry around this box just to drive 2 external monitors.

So, that means all laptops with only 1 display-out are out! (The X1 Carbon actually has a USB 3.0 Port thing with 2 DVI outputs but it seems to depend heavily on drivers (they only support Windows and are "working on" Mac support) so I've excluded it) Leaving us with:

- ASUS Zenbook

- ASUS Zenbook Prime

- Samsung Series 9 900X3D

- Samsung Series 9 900X3C

- Lenovo X220

- Lenovo X230

I used the Zenbook Prime and Samsung 900X3D in-store and initially liked the Zenbook Prime keyboard more than the Samsung. However more research reveals that ASUS seems to have big quality control issues with these (endless stories about shipping and re-shipping faulty units). This seems to be an especially big problem with the touchpads & SSDs of the original Zenbook. Also in the UK, they only carry one almost maxed-out Zenbook Prime configuration with SSD, which costs about 1500 GBP (linked above). A more sensible (albeit still expensive) configuration is also available, however only from Germany. Going through the order flow, the delivery time from Germany is listed as 3-18 days. Ordering an item like this where lots of people have complained about quality issues from another country seems to be asking for trouble. In addition to that, support under Linux seems to be non-straightforward https://help.ubuntu.com/community/AsusZenbookPrime, and I'm not thrilled about 1080p on a 13" screen.

The Samsung Series 9 looked great from everything I could see. It's super light and yet solid. However since it is so thin the keys lacked notably in pitch. It's uncomfortable to type on (and I went multiple times over multiple days). In comparison I enjoyed typing on the Macbook Air much more even though it's similarly thin. The keyboard seems like an afterthought on the laptop. Since typing is really what I care about the most and I've gone through the pains of having a laptop with a keyboard I don't enjoy typing on with the model I'm currently writing this email on, this also seems like a sub-par choice.

So the Lenovo X220 / X230 is the last laptop standing! There are 2 choices here (or really 4 with the tablet versions), they are all pretty much twice as thick as any other model, though similar in terms of weight (others 1.1-1.5kg, X220 / X230 1.3-1.7kg depending on configuration). I think the X220 is the better choice here even though technically "discontinued". They're both standard voltage CPUs (compared to some of the ULV CPUs on other units) so performance is easily enough for my needs. In addition to that the X220 seems to be the laptop of choice for Ubuntu kernel developers http://www.hnsearch.com/search#request/all&q=x220+uds , while I've read about a lot of people having problems with the X230 and the Linux 3.2 kernel (Ubuntu 12.04 and Debian Wheezy). Also with the X230 they've switched from their traditional ThinkPad keyboard design to a chiclet-style keyboard for reasons that are not ultimately known to me, though probably some combination of standardisation (every other major vendor has been using them for years), cost-reduction, ability to add back-light, size reduction and other factors. In terms of typing experience there isn't a lot of data online, with some people saying it's "good" on both and others decrying the typing experience on the X230. I think the X220 is slightly preferable, especially considering how much cheaper it is now. The standard X220 goes for 600 GBP and 825 GBP for the tablet version while the X230 goes for 1100 GBP and the tablet version for 1700 GBP. All of these with HDD and thus requiring adding about 200 GBP extra for a SSD. So it seems that the X220 wins in almost all regards. The X230 does have slightly less weight (I think about 100-200g), and faster CPU/GPU performance but those factors are negligible to me. I think I like the tablet version on the X220 more as comes with an IPS screen and I can see myself use the laptop in "tablet mode" a lot.

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In the end I picked the X220 and ordered it off ebay (new). The gist seems to be that unless you want to run a bleeding-edge Linux kernel I would recommend staying away from new (3rd gen Ivy Bridge e.g. i5-3xxx) laptops such as the ASUS Zenbook Prime / Lenovo X230 / Macbook Air 2012 as there's frequently issues w/ them.