Almost impossible to find info on eighter one, let alone "why this over that"

What motors should i go for and why ?

Going to be a big machine. ~700mm'ish. To be determined.

I want to use high speeds and high acc -values, but i also want to retain accuracy.

N17 or N23 and why?

Nema17s are cheaper, but the Nema23s also still fit my budjet, including their external drivers, so is there any downsides going bigger?