I'm tempted to do the same myself, but man, how can you live without apt-get and dpkg? I haven't looked at FreeBSD for ages; in OpenBSD packaging and patching is quite a pain, and this is holding me back a bit.
To be honest, I'd rate pkg-ng higher than apt and dpkg these days. It's faster, cleaner, and uses an SQLite database as the backend, which allows for much more interesting queries for figuring out system state. For the base system, FreeBSD has an in-place binary updating system called freebsd-update that works rather well. I'd definitely encourage you to try FreeBSD, it has a beautiful amount of cleanliness that's missing from current Linux distros.
FreeBSD has a binary package manager (pkgng) that should feel much like apt. The ports tree still exists if you want to customize and build from source, but in general you should be fine just using pkg.
There's no "should" about it. It does feel like APT. (-:
I invoke aptitude install on Debian and pkg install on FreeBSD/PC-BSD. dpkg -b stage/ target/ on Debian; pkg create -r stage/ -o target/ on FreeBSD/PC-BSD.
Bear in mind, of course, that the SVID package management is a clear precursor to both of them.
