I'm going to stir the pot here, just because I'm a jerk like that
My impression with the claims that polygraphite bushings initially squeak and bind upon installation is because the graphite they're impregnated with has yet to form a "coating" on the parts that the bushings contact. P-S-T claims that after a certain break in period, they will quiet down and not bind.
For the sake of noise alone I wouldn't put a polyurethane bushing on anything that can't be greased (save for sway bar bushings, and I have yet to hear a single sound from the sway bars on my truck since I put in polyurethane bushings about two years ago), because dry polyurethane on dry metal is bound to make noise and bind one way or another. Obviously, the severity will vary on a case by case basis.
That said, when I broke down, cleaned and reassembled (to add an extra leaf) the leaf springs on my truck, I sprayed each leaf and the teflon strips between the leafs with a graphite based lube called Slip Plate. The stuff worked so well it was a HUGE pain to reassemble the leaf springs because the parts slid around so much. Obviously, it didn't stay in place forever and washed away after about a year, but that was plenty long enough for the new leafs to break in and I still don't get any noise or binding from my leaf springs (which also have greasable shackle pins and polurethane bushings), and I frequently drive over VERY bumpy, washed out logging roads in the mountains.
This leads me to think that spraying the polygraphite bushings (I plan on getting a full set from P-S-T) with Slip Plate before installation will help prevent binding and noise during break in, and will add to the handling benefits of tubular UCAs if/when I order a pair.