Hello Kevan,
I have a MKI and MKII hybrid, and rate them both, considering their size and price-point. Because they were hand-made it also means they can fixed/repaired and upgraded. Prices vary, but like all machinery you have to carefully inspect before purchasing, and you usually get what you pay for. There are some specific things to look for. A lot is down to the original build but also what the following owners do or don't do them. I've learned from hard experience that some problems are costly to put right. A good DW is a useful machine and a pleasure to use; a bad one is just plain frustrating. I agree with all of the above, but registration becomes less of a problem if you use a collet chuck (e.g. ER25), and plan ahead.
Prices:
Unseen, need work, tired (worn), desperate for space: £300-£500
Decent to good condition, components (including bearings) with plenty of life, accurate, smooth running, mostly standard, well maintained: £500-£750
Excellent condition, excellent build quality, well maintained, omponents (including bearings) with plenty of life, accurate, smooth running, with extras (e.g. DROs, drill stops, gearbox, VFD etc.); usually MKII but could be MKI: £750-£1200.
If you're anywhere near Surrey you're welcome to pop in, have a chat, and try the MKI; the MKII is still under construction.
I may sell the MKI when the MKII is done.
All best, Aaron