Call me old school, but I like looking at the number of lines of code to get a feel for how big of a project something is. Mako[1] is 265,618 lines of code. The most widely accepted Bitcoin implementation[2] is 639,074 lines of code -- that's 2.5x bigger and written in a slew of languages. Mako looks like a super-impressive amount of work (and by a single person no less).

[3] How I calculated: find -type f | sed 's/.*/"&"/' | xargs wc -l

EDIT: Also of interest is this "from-scratch tour of Bitcoin in Python" that was discussed here on HN a few months ago: https://news.ycombinator.com/item?id=27593772