Hi Parker,
I recently strongly considered getting a
fiberglass tank when the old (no longer legal to fill with old valve) propane tank on my
Boler was getting close to empty. In my case, the propane company was actually selling them (i.e. no reluctance to fill them).
I think I read that there is only one state (LA?) that has problems with them, and even that might have changed by now. I can't imagine that too many places would not fill them these days, but I can't say for sure (thing is, at least where I've been, most of the "marginal" type places only exchange cylinders now anyway, so most of the places actually filling them are "pros").
I didn't end up buying one, and here were my factors:
1) They are more expensive, but that didn't really put me off for a one time purchase.
2) They are lighter, which would make them easier to handle and lighter on the tongue, BUT when you really think about it, they are the largest percentage lighter when empty (9# tare
weight vs. 18# tare weight for a 20# tank), but much less of a percentage lighter when full. That is, the propane in the tank weighs the same either way. So the weight "loss" wasn't as great as it first appeared. 9# at best for my one tank.
3) The clincher for me was that I would have had to modify my perfectly good tank hold-down system. It would have to be completely different to hold down a fiberglass tank.
So, considering all of the above, I went with another steel tank. At less than $30, I figured I can change my mind in future if I want to. That's not to say the fiberglass tanks aren't nice though. I was close. It was #3 that put me over the edge.
Raya