TRS-80 4D boot/diagnostics floppies

Hi. I think I'm gonna snatch a TRS-80 at work. I was going to ask opinions about whether the 4D or the 4P is the better choice, and I guess I am listening, but I think the Desktop is just too cute not to have. I think it's unmodified, with 2 floppies and no peripherals that I've found. Case looks excellent, keyboard is all there and legible. What should I be looking for, both in the way of problems and externals? I know there diagnostics disks or boot floppies available in .dsk format, from playing around with xtrs. Can I reliably wite them to floppy on PC? The FAQ says Tony Duell's utility is "convenient...if you can get it to work". ??? Does that just mean "if the operator has a clue"? Should I just leave the thing on the shelf? And the burning question of the day: But will it run Unix? Doc