Uncle Pyotr is way too optimistic, and doesn't always back up his opinions or estimations all that well (with a few notable exceptions).

At the same time, he is sharp, clear headed, and can see through normative ideas and explain in plain language the failings of those ideas and his counterproposals.

His material analysis, which in a couple of occasions (both having to do with the production of food) is backed by numbers surprisingly well, is of course very dated. He claims that we can produce nutritious food for everyone and cover all other needs, by asking everyone to put in about five hours of work a day, leaving the rest of life for artistic, leisurely and even scientific pursuit (he curiously includes science here instead of in the work part). That cannot be trusted, but it can be used to make arguments about today: with current technology and industry, we can probably beat his predictions.

His quantitative arguments (and even the qualitative ones) aren't supposed to be taken as gospel anyway. Uncle Pyotr ends the book with this passage:

With our minds already narrowed in our youth, enslaved by the past in our mature age and till the grave, we hardly dare to think. If a new idea is mentioned — before venturing on an opinion of our own, we consult musty books a hundred years old, to know what ancient masters thought on the subject.

Solid burn to us, his readers, even from hundreds of years in the grave.

All in all, the book is a source of surprisingly solid ideas to argue about anarchist communism today, even though is doesn't answer everything and it doesn't do that well in backing up some of its claims. What it does excel at, though, is clear, simple language.