I have a variety of computers, ranging from a desktop (Acer Veriton M460) through Thinkpads of several kinds, both 64-bit and 32-bit. All run OpenBSD.
OpenBSD was probably the easiest OS to install that I've ever tried. By simply following the defaults (except for choosing the uk keyboard) I found myself, after about 15 minutes, with a working system including X
. Everything else worked as expected too, including sound, which is often something you have to struggle with in Linux.
Installing third-party applications such as Firefox was equally easy. OpenBSD does have ports via a scheme borrowed from FreeBSD, but you don't need to use them since all the ported stuff also exists on OpenBSD as packages, and you are encouraged to use those instead of ports. (You only need ports when you want to modify a supplied program.) I found that nearly everything I wanted existed as a package so getting my system into order was pretty easy.
But of course nothing is ever as simple as it seems at first. Coming from a Linux background I had to adapt to new ways of thinking. This particularly applies to updating/upgrading the system.
In Linux this normally involves downloading and installing new packages and their dependencies, and you can do this in OpenBSD for third-party packages, which are mostly ported from Linux. But doing so won't work unless you upgrade the base system at the same time. There are several ways of doing this.
1. There is an official "-release" every 6 months, in May and November, from which you can upgrade your system.
2. There is a "-stable" branch which only gets serious errata and security fixes; you have to compile this yourself from source and it doesn't get you anything new (so you can't install new versions of third-party packages, since they won't work). This could be compared to Debian Stable.
3. There is also a "-current" branch, in which the developers post their new code. It is updated frequently both as code and as "snapshots". There are differing opinions about the desirability of using this. You can read dire warnings about the possibility of finding yourself with an unusable or even unbootable system, but plenty of people do use -current on production machines. I've now done numerous upgrades (using snapshots, not compiling from source) and there have been no serious problems. Snapshots are roughly comparable to the Sid branch of Debian, but remember that they are only concerned with the core system of OpenBSD. Packages are separately maintained and have to be installed separately.
Keeping OpenBSD up to date with snapshots and packages isn't difficult although it does take a little time to do. But you don't have to do it too frequently — just when you think it is necessary, perhaps because a new or updated package that you need has become available.
POSSIBLE DISADVANTAGES IN USING OPENBSD
1. The number of packages available for OpenBSD is smaller than on most Linux distributions. I found most of what I needed but in a few cases (qsf, sitecopy) I had to compile my own from source.
2. Some packages are rather old. Mostly it doesn't matter too much, but it can be a problem. For example, I had a lot of slides made with LyX and Beamer on another machine, and when I wanted to edit these I couldn't because the OpenBSD version of LyX was not compatible with the one I'd used previously. (LyX was updated a month or two later for OpenBSD.)
3. Some things I looked for simply don't work on OpenBSD. One of these is Flash, which is needed for BBC iPlayer. There is no Flash for OpenBSD and most people who use the system don't want it anyway because of its poor safety record. A possible way round this is to use get_iplayer. [Note added 01/04/2016: BBC now provides HTML5 as an alternative to Flash and this works well with Firefox and Chromium.]
Skype is also not available for OpenBSD. If you need this you will have to use Linux.
4. My flatbed scanner (Epson Perfection v330) needs proprietary software that isn't available for OpenBSD. So I brought back my Epson Perfection 1650 from abroad and this works out of the box with the sane backend. Incidentally, I think this now-superseded model is a better scanner than the v330.
5. To get round these and similar difficulties it would seem logical to install OpenBSD and Linux on the same machine and dual boot, but although this is technically possible it's harder to do than you might expect. You are probably better off using at least two machines rather than attempting to dual boot. Virtualisation is another possibility but I haven't tried that.
6.. Finally, if you want to use OpenBSD you have to be willing to learn a lot of new things. (You might say that's a feature not a drawback since it helps to keep your brain alive!) At first glance OpenBSD is quite similar to Linux but on closer acquaintance numerous differences appear. The OpenBSD folk pride themselves on their documentation and are right to do so, but you need to read it carefully and do a lot of googling rather than ask newbie questions on the mailing lists, which are a lot more technical in tone than those of most Linux flavours. (DaemonForums may be a better place to ask beginners' questions.) Absolute OpenBSD
(2nd edition) by Michael Lucas (ISBN-13 978-1-59327-476-4) is certainly worth getting if you decide you want to run OpenBSD regularly on one or more machines.
Currently OpenBSD is the only OS that I'm using.
For a comparison of OpenBSD and FreeBSD for the desktop please see Which BSD as Desktop