Based on using CentOS + DKMS, Debian + DKMS, and Arch + DKMS :) Some of these have prebuilt modules too, but as community projects they usually lag behind kernel releases to the main distro, and that can be a problem. So I always end up using DKMS.
Not used Ubuntu ZFS, admittedly. Haven't used Ubuntu since 2010 or earlier.
Is that true? RHEL/CentOS have both DMKS and kmod versions; in Ubuntu ZFS is a supported package. That's not most distros, certainly, but it is the ones most people use.