When comparing OpenRC vs runit, the Slant community recommends OpenRC for most people. In the question“What are the best Linux init systems?” OpenRC is ranked 1st while runit is ranked 2nd. The most important reason people chose OpenRC is:
OpenRC follows the UNIX philosophy of 'do one thing and do it well', while it's true that it has more features than sysvinit, it does not stay away from its primary function with unnecessary added features.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro No feature creep
OpenRC follows the UNIX philosophy of 'do one thing and do it well', while it's true that it has more features than sysvinit, it does not stay away from its primary function with unnecessary added features.
Pro Extremely simple
All configuration is done via shell scripts and symlinks. Shell scripts can then use various specialized utilities to ease the development of init scripts.
Pro Fast
OpenRC builds on top of sysvinit and adds some more useful features (like parallel booting) while still the simplicity that sysvinit is know for. Because of this it generally boots faster than other init systems, especially when parallel booting is enabled.
Pro UNIX-Like
Does one thing and does it well.
Pro Less dependency creep
Using OpenRC does not lock in a distribution by providing specific NON-POSIX extra services which programs then would rely on.
Pro A very balanced compromise
Basically OpenRC doesn't replace SysV init, but rather works with it, providing features that SysV is lacking while taking advantage of its benefits. It's also used by a fair amount of reasonably popular distros and is well supported and developed.
Pro Very efficient on system resources
Uses multi-core and ram very efficiently.
Pro Portable
It can be ported to other UNIX and UNIX-like operating systems.
Pro Flexible and extensible
I can add a new startup script for most cases in under five minutes. The ability to quickly insert new applications into the system is a big help.
Pro Not bloated
Pro Deterministic
It always initializes a system the same way; if OpenRC booted and ran a system properly today, it will boot and run properly tomorrow, and the next day.
Pro Fast, parallel startup
After the system's one time tasks (stage 1) are done, the system services are started up in parallel. The operating system's process scheduler takes care of having the services available as soon as possible.
Pro Small and Unix-like
One of the runit project's principles is to keep the code size small. As of version 1.0.0 of runit, the runit.c source contains 330 lines of code; the runsvdir.c source is 274 lines of code, the runsv.c source 509. This minimizes the possibility of bugs introduced by programmer's fault, and makes it more easy for security related people to proofread the source code.
The runit core programs have a very small memory footprint and do not allocate memory dynamically.

Pro Easy to use
Simple scripts linked to the proper directory is all that's needed to bring a service up at boot, and everything is up and running quickly.
Pro Init purity - does what an init system must do and nothing more
UNIX philosophy, easy to add new services, easy to manipulate, really fast.
Pro Supported by several Linux plumbers
Myself included. Development is no longer stalled.
Pro Runs on every POSIX system
Pro Fast and easy to use
Pro Faster boot time than with systemd
Faster on older systems, especially those running on HDDs.
Cons
Con No socket activation
OpenRC does not have socket activation yet. It will be added in the future though.
Con Not widely offered across distrubutions
From Distrowatch, only ten distributions (of which 8 Linux, 1 BSD) officially support OpenRC, and offer it through their standard repos.
Con Not GPL
Con Not GPL
Con Slow
Con Development stalled
Last patch was back in 2014.
