Just tried from my home connection, it's a lot faster indeed. Nice initiative!
time npm install forever
real 0m9.392s
user 0m4.830s
sys 0m1.254s
time npm --registry http://registry.npmjs.eu/ install forever
real 0m4.540s
user 0m3.890s
sys 0m1.049s
Tried it from Stuttgart. The speed increase is huge. Not sure if this is because of the location or the fact that NPM official servers are overloaded though.