Today I testing out systems in a store, trying to decide on my next computer purchase. MacBook Air or MacBook Pro, and if Pro, go Retina or not ? The Air actually does a lot of tasks faster because of the SSD, which the Pro with Retina also has. But if one compensates for that by putting SSD into the non-Retina pro, the price comes out higher than buying the Retina right out. Except the Pro are in stock and the Retina are 3-4 weeks (partly because everything is soldered into the Retina version, nothing changeable at all!)
So I'm in a struggle: price versus screen real-estate. Oh yes, and for compute-heavy multi-threaded tasks, the Pro and Pro with Retina are much faster (more cores, and they have a GPU that supports CUDA.) And the Air is lighter. But I anticipate doing a lot of authoring, and the 15" screen you can get on the Pro does make a difference for that purpose compared to the 13" max for the Air. I did enough testing to see that I could write things on the 13" if it was necessary, but also enough to see that it was too small of a display for someone using their computer a lot. I'm on an older 15" PowerBook now and have been for a couple of years and it has been OK. But I could not imagine working days on end on an 11" or smaller screen.
I would note for this purpose that visual field is more important to me than to most people. I get my glasses with some of the widest commercially available lenses. My active field of view is a bit more than twice the width most people would purchase at: smaller views bug me. And this perhaps affects my impression of suitable screen sizes: it could be that to some people, 11" or smaller would be perfectly fine. But not for me.
If I am going to be doing something like MATLAB, I want the execution area and the editing area to be simultaneously visible, or when I'm programming, I want the edit area to be visible while I bring up a documentation page.
So where I am left at the moment... contemplating getting the 13" Air as being "good enough" for working alone with for a time, and getting the DVI connector cable for plugging into a real display. Yes, the Pro has notably better performance, but the Pro is still not you buy if you want a high performance machine: the Mini and the iMAC can give you better performance, or you can wait for the next refresh of the "Mac Pro" tower machine (available in 12 cores now, but the per-core performance is no better than the MacBook Pro). And if you want a performance server, put a Linux on top of a box from Liquid Nitrogen Overclocking
Did I mention the price? The 13" MacBook Air would cost about $1680 in the configuration I would need. The 15" MacBook Pro without Retina would cost over $3200 if I ordered it with 512 Gb SSD to match the baseline version of the Retina. I could theoretically drop the price down by going with the Retina version... but since the RAM itself is soldered in to the Retina version, if one is contemplating ever needing to upgrade past the 8 Gb RAM, one needs to order the 16 Gb option at build time. And expect a 3-4 week delivery on the Retina version... Even if I ordered the Pro 15" without Retina, 1-3 day delivery (I would special-order the anti-glare screen), and did not upgrade the CPU to its top end (2.7 GHz instead of 2.6 Ghz), it would still be literally $1000 more than the MacBook Air.
Under-buy a little now, plow the difference into the next computer? Buy the maximum available portable now and keep it for years, as is my usual practice?
Decision, Decisions, Decisions.
But if I were looking at netbooks, matching specs against the 7 year old portable I have now, I probably wouldn't bother to buy anything new at all, if not for the fact that MATLAB is no longer supported on the PowerPC CPU.