I have a SH-101 and really like them. I think the current prices are very fair for what they are.
If I had to choose only one hardware synth, I'd go for a Virus TI (obviously!
). If I could choose one modern and one vintage synth, it'd be a TI and a 101. The 101 is very limited compared to a Virus, but what it does, it does very well. There's a good 'weight' to the sound and it sounds very solid in isolation, without having to add external effects, compression, etc.
I'd also recommend them to anyone wanting to start learning synthesis, the simple signal path and slider/knob for every parameter makes it very easy to get your head round. The aesthetics of the hardware itself are beautiful too. I don't know why; looking at any one part in isolation it looks clunky and even cheap-looking, but together, it all works as a whole and is probably my favourite looking synth of all time, particularly in the (most common) grey colour.