The recent production "classics" I have examined have been well made, both the 27 and the 29. The street prices I have seen are about $750/$800, sometimes specials for less. The nickel models were exceptionally well finished.
You may be able to find an older one in high condition for a little less. You should be able to buy one with confidence as they are
almost always nice form the factory, though some lemons did get through.
A new gun will offer that "new guns smell" (satisfaction), lifetime warranty, and box/etc.
Keep in mind if you want a 4" model, these on the used market bring a premium (and they were 3.5" up until 1980 or so, then 4"). Those will cost you as much or more than a new gun. Here's a fairly typical example of a used sale, and would have run $875/900 to get it home:
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=145314374
Either new or used is an OK buy. Finding a high-quality older one can take some work, patience, and time.