dnf, the experimental fork of yum was introduced in Fedora 18. Under the hood, dnf uses the libsolv library from openSUSE (also used by Zypper) and aims for near 100% compatibility with yum. Nearly all command line options are the same and instead of /etc/yum.conf, it uses /etc/dnf.conf but the configuration options are not changed. dnf is parallel installable along side yum (yum install dnf) and the plan (30:05) is to make it the new yum only by Fedora 22 so you have ample time to participate.
I have setup a bash alias (alias yum=’sudo dnf’ in ~.bashrc and source ~/.bashrc) in my system that pretends that dnf is yum so that I don’t have to throw away my muscle memory. In the course of the last several months, I have filed over a dozen bug reports and new feature requests (mostly to bring dnf in line with what yum already supports) and the core dnf (especially in Fedora 19) is usable (with the exception of one weird bug) and the performance is much better compared to yum. There are quite a few nice features missing however. This includes support for Delta RPM, history undo, parallel downloads, auto-remove, bash completion and several group commands.
Try it out and report any bugs.