hm.. usually my trigger element for used watches are focus on rare model / limited edition ie Rolex 1680, Panerai 5218-201A etc.
Also budget is the key concern la..
As for new watch, simple.. deal in peace for the condition, risk-less on replica aspect, also the "virgin" feeling lo..
Last but not least, provided u have deep pocket as well
Just some humble opinion as per my perspective..