We just had a thread on these about a week ago.
I checked into switching and there were pros and cons. Personally, I don't think I would worry too much about people not filling them, but here's what I came up with:
1) The composite tank is more expensive, maybe about $100 compared to about $30
2) The composite tank is lighter weight
, but that advantage becomes considerably less when the tank is full, because the propane
weighs the same either way.
3) You can see the level in the composite tank, whereas you have to pour water on the steel one, or use a stick on gauge or something else less obvious.
4) The composite tank will likely not fit in your existing hold-down bracket (this was "the straw" that made me go steel, at least for now).