As good as the reviews say!
After much deliberation I decided to go for another Bilt-Hamber product, a trade-off of trusted brand vs. price. Put it to work straight away on a customers alloys which were coated in mud, grime and brake dust. More than anything, it's just fascinating/uber satisfying to watch it turn a dark purple-ish colour as it begins to react with the contaminants.
I've not had a chance to compare it to other big name brands yet so I can only give it 4 stars but it worked very well. I needed to re-apply it a couple of times, but without using a wheel brush I think that's to be expected. I'd agree with other reviewers that the smell is somewhat horrific but if you can get past that I'd highly recommend this