I like the way it builds up through the sequence of most common to least common (in English) letters ETAOIN... instead of focusing just on "home row" keys like

I like the way it builds up through the sequence of most common to least common (in English) letters ETAOIN... instead of focusing just on "home row" keys like Mavis Beacon used to, which I always found artificially hard because it meant lots of side-ways combinations. Both of course have their limitations in terms of appropriate words or chunks however.