Yeah I've used both.
The WALK was my first mod, and I used the later black bushing version. I did get very noticeable ovalising of the hole that supports the control arm, which caused some tramlining the worse it got. It's a common problem with urethane bushings known as 'creep and set' and is precisely why OEMs don't use it on their production cars. It took about 3 years of daily driving to get that bad though. The WALK adds 0.5 degree caster.
I now have the SALK fitted (the harder 90 shure version) and so far so good. Not enough miles on it to form an opinion on the wear characteristics, but to me the SALK looks and feels a lot better made. The SALK adds 1 degree of caster.
In summary, I'm not an advocate of poly on road cars at all, it has no place on passenger vehicles. That said, if you are aware of and accept the wear characteristics, then the WALK and SALK are a lot better than the original rubber consoles, but not massively so. You're not going to rejoice loudly from a building top.....it's a subtle, but worthwhile improvement.
I would consider the OEM S3 console bush if you want a fit and forget solution.