I don't like poly. Polyurethane is a sticky plastic that adds unnecessary friction to the suspension.
I made a set of delrin bushings a while back. I'm replacing them with UHMW now. Needless to say I think that UHMW is a better material for this application. However, UHMW is UMHW, and there are many varieties of delrin which may be more or less appropriate to suspension bushings. The variety I had at the (incorrect) clearances I was running did not do well.
I recommend 8shark's UHMW bushings. I haven't used his bushings though, as I'm making my own.
Another thing to consider is XL-UHMW. It has better NVH characteristics than regular UHMW, although it is quite hard to find.
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'87 Fiero GT: Northstar, Getrag, TGP wheels, rear sway bar, rod end links, bushings, etc.'90 Pontiac 6000 SE AWD: Leaking ABS unit fixed, load levelling rear suspension fixed, still slow