Any experience with a Giant Yukon SX or Kona Four? They're about all I can think of for a decent all-round DS bike with a budget of no more than $1800.
Use is general trails, eg Manly Dam, Red Hill etc, not out to win XC comps (and not a lot of choice at that price range).
The Giant seems well spec'd for the price, although a tad heavy. I imagine the Kona would be similar if not heavier though?
Any particular reason you want a duallie vs. a hard tail?
FS bikes that are sub 2.5k tend to be too heavy, have cheaper parts, and the bushings/bearings aren't exactly top of the line stuff either, all meaning that it could be a very high maintenance bike.
Below 2k, most people are better off looking at a hardtail, and you can get very well specc'd hard tails in this price range.