mmdebstrap is nice tool, but newest deboostrap is not so bad :)

mmdebstrap is fast because it uses apt for package dependency resolution and download. Yeah, it's true, almost right - but most of the reason for "fast" is just about "downloading packages", I guess.

debootstrap uses wget for download packages, it's serial execution so it waits for each download and mmdebstrap - apt does not do so. If you use "--cache-dir" option for debootstrap, exec time is almost the same.

$ time sudo mmdebstrap unstable unstable-chroot
(snip)
real 2m58.670s
user 0m23.559s
sys 0m26.387s

$ time sudo debootstrap sid sid
(snip)
real 7m22.955s
user 0m57.450s
sys 0m37.894s

$ time sudo debootstrap --cache-dir=/home/henrich/tmp/cache sid sid
(snip)
real 2m44.752s
user 0m54.504s
sys 0m33.666s

Anyway, I should consider "--use-apt" option or something for debootstrap - for future release :)