I just went back to Aptosid to do a test and I think that Aptosid is somewhat snappier at the moment than Arch.
The big drawback of Aptosid is the time consuming update that you have to do in init 3 as root.
So you can't do anything else while you can update in Arch while doing your usual stuff. (While controlling the terminal output of the update process of course on useful messages..)
Tip for dist-upgrade in Aptosid
If you do while still being in X
and after that
#apt-get dist-update -d
You can do all the preparations in X as you will be only downloading everything you need.
But still after that going to init 3 logging in as root and updating etc now with
# apt-get dist-upgrade
will take you some time anyway.
#init 5 && exit
I quickly adapt my grub menu.st file to the newest kernel as my aptosid partition doesn't contain the dominating grub installation of my hard disk.
Also something you don't usually have to do in Arch; happily, because every 6 hours there is a new kernel in Arch...