"Why do you use that proprietary, obsolete old junk?"
1. It's cheap. In the rush to avoid the Y2K non-event, a great many of these machines have been retired, mainly due to a lack of understanding about what real Y2K compliance was. There is also a perception (partly true) that they won't run a lot of the high-powered networking and e-business applications that businesses think they need these days.
2. It's robust. It is some of the best constructed PC equipment ever made. I was once told that PS/2 machines were designed with an intended service life of 10 years, with regular maintenance. That's 24 hours a day, 7 days a week, in the case of the server machines. This is emphasized in this quote from Tony Ingenoso, who used to work for IBM:
3. Because these machines are considered 'obsolete', parts and accessories can be found cheaply as well (Ed: Not anymore...). EBay is a great source.
4. Engineering excellence. Technically knowledgable people who are familiar with the PS/2 line appreciate the well-thought elegance of the Microchannel design. Even today, it is considered by many to be a technically superior bus design. Take a look at the article 'MCA: The Sacrificial Lion', from the IACT, located HERE.
For a layman's explanation of why Microchannel is superior, look HERE.
5. They run well. Performance is very good with DOS, surprising with OS/2 or Linux, and the higher end machines even run Windows NT 4.0 quite respectably when properly tuned. And we generally don't see the hardware compatibility problems that exist to this day with other x86 architectures. Plug and play? Microchannel defined the concept.
6. Very well-shielded. In my ham radio hobby, I typically deal with weak to very weak radio signals in the 3.5 to 500 MHz spectrum. I have never had any perceptible RFI in the ham shack from a PS/2 machine, while some other computers will wipe out an FM radio at 100 yards before you even turn them on (OK, I'm exagerating a bit, but you get the point)! They also seem completely immune to transmitted energy in the 100 to 150 watt range; I have machines that are physically connected to radios for various reasons, and have never had a crash that can be attributed to a radio transmitter 'getting into' the computer. PS/2 computers are arguably the best computer to have in the ham shack.
7. Distinctive. This ain't no bubble-packed, off-the-shelf clone from Best Buy or Office Depot. This looks like some serious hardware. Maybe using a $12,000 server machine to do contest logging or capture data from spacecraft is a bit of overkill, but it's a kick for the ole ego....
8. Friendship. The comp.sys.ibm.ps2.hardware newsgroup is one of the finest group of folks I have ever run across; I have made friends and acquaintances, and swapped hardware and stories, with people all over the world, with all sorts of different 'day jobs' and life outlooks. I was welcomed into the group as a 'newbie', and I feel that I have been enriched by the experience.
All this from a stupid computer? It hardly seems possible.