Having just read "Ideology and Terror", I have to say it seems to set up a "totalitarian" strawman that sounds much closer to life under Big Brother than with what I've read of life under either Hitler or Stalin.
Interesting ideas, but I'm not sold on the idea there was anything new beyond Tyranny/Oligarchy with a more focused sales pitch.
Key difference over tyranny is that totalitarianism is necessarily an expansionist movement with global aspirations, whose enemy is any truth or belief that could enable people to find a basis for agreement against it. It's total dominion of the human spirit through terror, where traditional 'isms are just nationally focused. When you break people with the randomness of the terror, they will oppress themselves.
In this model, North Korea is still just a national tyranny, and even China's CCP is a national police state with colonial aspirations, but it hasn't metastasized into a transnational movement. Hitlerism and Stalinism were the result of movements that created totalitarian empires. Arendt's view was it was a new form of government that was an artifact of the 20th century.
If Waterloo hadn't happened, (and leaving aside expansions on the other side of the Atlantic) would the French Empire have counted as totalitarian? It had an official emperor, and they definitely tried to export revolution.
Interesting ideas, but I'm not sold on the idea there was anything new beyond Tyranny/Oligarchy with a more focused sales pitch.