I got a 1200 on ebay at an alright price, but you may want to consider AmigaKit. Ive seen basic 1200s sell for insane prices on ebay... AmigaKit sells refurbished (or even new machines from old inventory) 1200s with optional add-ons like bigger drives, RAM boards, software, Compact Flash readers, etc. Much less hassle than ebay and without the artificially inflated prices as well!
I've never been happy with the results from UAE (WorkBench looks fine, many demos and games run strangely) though some people seem to love it.