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The joists that are "are particle board with a 2x3 on the top and bottom" _are_ web joists. Perhaps you're leaving out the "open" in "open web" but that makes them structurally a truss as outlined in another posting that outlines the difference between the two design forms of a lightweight structure to support a load over a span. As noted therein, the truss accomplishes it by causing a set of members to act in (nearly) pure tension/compression w/o any significant bending forces whereas the other uses a (constrained) solid web to provide the resistance against bending stresses.
That the risk from failure of a structure owing to a plumbing leak causing a failure of a web joist is pretty well demonstrated by there not being in wave of such occurrences.
As for the height, there's always a tradeoff--there is no free lunch. As compensation for the higher wall height as another noted there's the payback of an unobstructed ceiling w/o dropdown duct chases and the like for finished basements/lower floors as a payback. Whether that is or isn't sufficient benefit in your mind it certainly is in many. I'll comment that I like it very much in the house in TN altho it was a purchased on-spec house and hadn't thought about it to any extent (as in at all) before and it wasn't a real factor in the decision to purchase. But, it was _very_ handy when finishing the remainder of the basement for pulling additional wiring/plumbing runs, etc., and the plain ceilings were also a plus.
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