They suck imo because they are a PIA to install. You have to use your old pressed in outer shells. The main reason though is the do not function like a oem rubber bushing. It is also one area that is hard to keep lubricated. As well as the increased ride harshness and shorter service life.
"I put a set of polyurethane control arm bushings in my '91 about 4 months ago. It made a big difference in NVH. Hitting bumps is a lot more harsh than it used to be. The biggest difference though is when sitting at a stop light when in gear (I have an automatic) It makes the inside of the car rattle and vibrate."
"Did it to my old 89 a few years back. big increase in NVH (noise/vibration/harshness) and no upside, other than worn bushings were gone."
"After a few months of daily driving the front end starting creaking and popping like an old door when going over bumps. I found the grease washed out of the sway bar bushings and the bolts for the lower control arms kept coming loose no matter how many times I rammed them back on with an impact wrench. I never even noticed any improvement in handling. Still felt the same way as the rubber bushings, although there was definitely more noise and vibration felt in the floor.
As I see it, the problem with the control arm bushings is that the OEM rubber has a steel sleeve with teeth that is molded into the bushing. The bolt when torqued locks the sleeve into the K member by the teeth biting in. "
"I can attest to ride harshness with poly bushings in the lower control arms. I replaced the lca bushings with Whiteline bushings, and hated the ride afterward. I ended up putting in new oem control arms with the rubber bushings, and the ride quality difference was night and day."
There are some quotes from around the web. Feel free to use any search engine
Not sure what more I can add here. I do not like posting here but I did post the link that answered your question on where to find them.
If you do use the oem rubber type make sure they are a bit older and have the visible ledge at the one end so you know the pressed fit will be proper. Some of the newer ones that were around did not have that and fit loose in the control arm.
This guy has three moogs for 50 shipped, you can clearly see the bit larger diameter on the one end.
Moog