So we can disagree, but i will call them thin clients, because that's what they are. You have consistently avoided to mention the price of these 'super devices'.
I will conclude by saying that the principle behind this super technology (Thin clients) is very good but the high costs involved in the acquisition will mean, they will be relegated to isolated installations around the globe (read Developing countries).

"Ultra-thin" client or "zero client" mentioned in this link is closest to what I consider a virtual desktop. Thin client is different than a PC in that the CPU is lower-end, has no hard drives or optical drives (uses flash). Costs are the about the same with a PC. Virtual desktops have no OS, no CPU, no HDD, etc. They just provide an interface for keyboards and mice. Software is loaded on a PC that allows multiple virtual user sessions to be distributed to multiple separate client devices.

You can get many of these questions answered through Google or Wikipedia.

I reference 60%, but we've seen savings on actual deals up to 75%.

The home use of the XO is one characteristic of it, yes, but even with home use, over time we are not seeing much "critical development" of the use of the software. At home they repeat the games (memorize, draw), and take more pictures.

Battery life at the thin client lab is 6 – 8 hours / day, the panels charge the batteries, which then go on to power through the inverter well after dusk.

If the delays in using the XO were not so frequent and time-consuming (flimsy touchpad, system crashes, etc), I would be more inclined to invest the project in them.

But I reiterate that warranty and tech support are not "apples and mangoes" as you say. The warranty is an indicative comfort, but realistically no manufacturer would be replacing or validating a warranty on a machine put in this environment. The actual benefit of a warranty is much like tech support: it exists on paper only.

It is not comparing the technology itself that helps students at the end of the school day, it is how they made use of the technology. In rural areas, where teacher training is low and access to support nonexistent, the thin clients provide a better service, simply put. I would be interested to learn what you mean by "using them optimally" in regards to the XO, because we have tried everything. What do mean by "optimally" exactly? That which engages the children and excites them about learning? Because their favorite programs (Record, TamTam) are those which use up the most battery life. Should we have them doing rote copying from the chalkboard on to the XO, contrary to student-centered teaching, just so that we can "optimize" the battery life? Seems antithetical to the project's purpose.

I should note I wish we were on the beach, but no…just in the middle of a serious drought!