I was one of the original G1G1 participants, and I'm sorry to say that the gap between what was promised and what was delivered would never have been forgiven in any commercial enterprise. The "20 hour" battery life turned out to be 3-4 hours, and despite much talk about improvements to the power management software, nothing ever came of it.
The biggest disappointment for me was that the much-heralded "show source" button, didn't. I never quite worked out the tortuous explanations/excuses, but one of the original premises was that all of the machine's source would be available for inspection and modification--to kids, if sufficiently bright. In reality, all the enthusiastic video demonstrations of the "show source" feature were just showing ordinary browser HTML source, and as nearly as I could tell, the "show source" button never did anything more than that.
"Sugar," which I'd hoped would educate me in a brand new model for computer interaction, was, at the time, a bad joke with poor usability. The only way to locate journal entries was by remember to enter text tags for each one when complete, and doing text searches on the tags. It was explained that "fortunately kids like to describe everything they're doing." All usability objections were answered with the retort that I was not part of the machine's intended user base--true enough, and I have never verified for myself whether eight-year-old kids using the OLPC laptop really do type in text tags to enable them to locate their documents.
The one practical use I meant to put it to, as an eBook reader for PDF documents, didn't work because the PDF reader program was buggy, crashprone, and--even when it didn't crash--didn't save your place in the document (and didn't have any bookmarking mechanism). If you stopped reading at page 56, when you reopened the document, you'd be at page 1 and would have to remember what page you were on and scroll to it.
Hopefully all of these problems have long since been dealt with, but it left me with a bad taste in my mouth.