I've been writing Python since 1998 and I had no trouble adapting to Nim's overall syntax in a matter of weeks, not just its syntax around return types.
I much prefer `:` (two keystrokes, one key for each hand) to `->` (three keystrokes, two on the same hand and both requiring moving the hand away from home row). Regarding typing speed, the colon is much quicker. Regarding ergonomics, the colon is more comfortable.
