Polyurethane bushes good or bad

We have the Blue Polybush in a couple of Land Rover's on the farm. So far so good.

When I say not all poly bush are equal. Is that in the case of Polybush, they offer 3 different grades. Blue is soft, Orange similar to OEM rubber and Red for stiff/performance.

Super Pro also use varying grades, but don't normally tell you much about it.

Lots of cheaper ones could be anything, some will be good and some likely terrible.

From my experience, if they're cheaper than the OEM style replacement bushes, they're probably rubbish. 
Then again, I haven't used them for many years, general no-name brand quality may have improved. 
I personally don't see any advantage in using them over OEM style in my Jimny, if anything I would want more flexibility, but your application is different to mine. 
My 2008 Jimny (nearly 200k kms) is still on all original bushes apart from castor correction in the front and the shock bushes. The original bushes I pulled from the radius arms to correct the castor are still sitting on my bench good as new. 

Years ago I ran poly bushes on a sport hatch (a 1992 Suzuki Swift), the handling was absolutely amazing, ride comfort was non existent, and for a vehicle that saw only street use, I'd say the wear rate was horrendous, despite the fact that the bushes were frequently cleaned & lubricated with the correct grease to get rid of the constant squeaking.

My needs have since changed and I can't see myself using poly bushes in the future.