Maybe it's a matter of taste, but I think powerflexing wrecks the handling. Standard (when not knackered) is fluid and secure. Powerflexed is rigid and skippy as hell. That's why Alfa fitted spherical bushes rather than much cheaper plastic/rubber bungs. I've gone from standard to powerflex and back to standard, so I am comparing like with like. My guess (and it is only that) is that people who think powerflexing improves the handling from standard mean that it improves the handling from knackered standard - and it certainly does.
...and I don't think Jamie rips anyone - he does great work and makes a living! When I've sourced cheaper original parts than he can supply and asked him to fit them he's perfectly happy, and when I've got the parts from him he's been in the ballpark competitive. What more do we want than that?
Yes - I had a 1997 TS from new, and replacing rear suspension arms as the rubber bushes failed was a regular and painful expense from shortly after the guarantee ran out! I used to buy MOT insurance a year in advance, knowing that it would fund at least one arm at the MOT next year.
My current car is a 2001 V6, so it came with spherical bushed arms. I had the whole rear end powerflexed as bushes were getting worn and I wanted the cheaper "fit and forget" option. I hated the skippy insecure handling so much, I've bought new oe spring pans and now doglegs, and that has sorted it completely, for me. I did have a Q2 fitted at the same time, though, so that's another variable, I suppose.
In the end, if it passes the MOT, and the driver is happy with the handling, what goes in the hole in the arm doesn't really matter.
Out of interest, How old were your rear dampers when you fitted the bushes?
I have found that those who fitted powerflex bushes and noticed that the handling was worse had either;
Not fitted them correctly - They must be well lubricated when fitted with copper slip and torqued to the correct torque.
Not fitted a full set, - Some don't bother to replace the upper arm bushes, not a good idea as the bush firmness should be balanced. No good having stiff lower bushes and soft upper bushes and would almost certainly introduce some "Skipping".
Have had knackered dampers - of course they don't believe it at the time, but when they then explain that they are on the origional dampers at 15 years old/ 100k miles it is obvious. Most twin tube dampers have an expected lifespan of 60-80'000 miles.
When I got my GTV, the handling was atrocious and yes, very "Skippy". When I found that the subframe was cracked i had to pull apart the whole rear end. I found that the bushes hadn't been lubricated at all so every pivot point was seized. The upper arms still had rubber bushes fitted but the dampers where sound (tested them by hand and they where only 2 years old). I wrote of every bush removing them so replaced them with a brand new set including the upper arms. I lubricated everything well and chiped off the built up rust so that the washers could be fitted where they had been left off previously. The results where astonishing and gave me what I would describe as perfect handling and ride.