Comparing the top output of the example.js from nodejs.org to an equivalent implementation in Perl using HTTP::Server::Simple:
VIRT RES SHR TIME+ COMMAND
614m 9512 4416 0:00.05 node example.js
28932 6408 2660 0:00.04 perl example.pl
node.js not only uses 1 1/2 times the amount of memory compared to perl, it also needed more CPU time for startup and handling a single request returning "Hello world"
So much for lean and fast compared to bloated Perl runtime crap.