You're only forced to use 64 bit userspace on slicehost if debootstrapping a 32 bit chroot and replacing the root filesystem with it live is too scary. :)
The real nice thing about linode is they allow running your own custom linux kernel.
Even were it a straight comparison, Linode is still cheaper, so why would I pay for the privilege of fooling around every time I want to set up a new instance?
If someone writes a tutorial, more people would do it. I wanted to when I was on Slicehost, but ended up just switching to Prgmr instead because it was easier.
The real nice thing about linode is they allow running your own custom linux kernel.