They are a really neat thing to play with if you're feeling nostalgic, I built one about a year ago and have spent many, many hours playing with it since! The build quality is excellent, support is great and with a v20 CPU it's one of the faster XT clones you'd be able to get your hands on. Here's my build:
- iStarUSA D-313SE-MATX 3U rackmount case with the ears removed (very boxy!)
- Mini-Box PicoPSU-90 with the 12v wall wart lifted from an old Netgear switch. The entire thing pulls less than 2A so even this is overkill.
- NuXT 2.0 board with v20 and 8087 CPU's
- IBM Model M keyboard
- Radio Shack trackball (bad enough to be period correct!)
- Mag Innovision 14" CRT (NOS but nearly destroyed in shipping, pieced back together with model airplane glue and a lot of bodge wires)
- TexElec Resound 2 OPL3 AdLib clone
- Serdashop CVX4 Covox Speech Thing Clone on LPT1
- 2-port joystick adapter
- TexElec 2MB EMS card (not currently installed)
- Racal Datacom Ethernet adapter (not currently installed)
- PPP over COM1 to a Mikrotik router as a "modem" for transferring files (Ethernet was boring =)
- 200MB Maxtor IDE drive (mostly for the noise, it's the D drive)
- High-density 3.5" and 5.25" floppy drives
Overall I'm very happy with it and glad I spent the $$$ and time to do it, my first IBM-compatible PC was a Compaq Portable and this provides enough of the same experience to bring me back. It plays old games like Lemmings, Railroad Tycoon, Civ1 and Sim City fairly well, which is actually not something an original PC or XT could have done.
Oddly enough the only thing I kind of miss and wish this had was my old Amdek 310A display that came with the 5160XT we got shortly after the Compaq, but those are a little hard to come by now. I did pick up a NOS CRT from an IBM 5155 portable that I intend to build a case for, and a CGA/MDA clone card with a composite output on it if I really want to enjoy squinting at a small monochrome display again. All the other modern things like PS/2 support, CF cards and upper memory however are well worth it.
