I keep going back and forth on whether to buy one, but I'm tending toward "no" -- a makerspace opened up near me and they have half a dozen different 3d printers but it usually seems that at most, two are ever working at the same time. Despite that, I recently needed an object printed, paid $50 for the membership fee for a month, then spent 13 hours babysitting a print. On the first try, it jumped 2mm on the X axis about 15 minutes into the print. Stopped, restarted, and after spending all day watching it, it jumped 2mm on X axis again with about 30 minutes left on 12 hour print job. Then I had to pay $15 for my scrap plastic.
I was pretty non-plussed, so I tried one of the online printers -- the type which use the very expensive powdered plastic machines -- my piece cost $65 which is pretty pricey, but they came out exactly like I expected. About 20 of those prints would buy a printer, and it is hard to resist that logic, except when I think back to spending an entire freakin day to get garbage and the fact that most of the printers at the makerspace are usually offline because a needed part is on order.
I'm not really sure what my ultimate decision will be, but the promise of consumer 3d printing seems to be more than it delivers at present.