[jstanley]

"easiest is to just hold down the keyboard key of the base letter"

Does this mean that you can't hold down a key to produce multiple copies of the same letter?

[to3m]

You can disable it - I've got it disabled on mine. I don't remember how, though. There are no obvious options in the System Preferences. I wonder if it's buried somewhere in Karabiner (formerly KeyRemap4Macbook).

[knodi123]

yes for space and tab. no for letters. in practice, I've never actually needed typematic repetition of letters, so it's a reasonable tradeoff IMO.