My 16s and 32 are Body Power, very affordable but very variable in quality. The 16s were both mostly okay but the 32 had a big casting seam from misalignment during casting and took a lot of work to make the handle more usable. And the paint is rubbish. But I use it every day and I can't say I feel cheated.
On a whim I bought a 24kg Men's Health branded one from Argos. It seems to have been designed by someone who has seen kettlebells but never used them. It actually looks like an 8kg kettlebell just enlarged. The handle is by far the thickest I've seen on any kettlebell, much thicker than on my 32. This was good grip practice when I was 1H swinging it regularly, but even with reasonably sized hands it's too scary to snatch much. The finish is good but unless you have giant hands I think it's too disproportionate to consider.
I will be buying a 40kg bell in a couple of months and I think it will be a Strength Shop one - they seem quality and reasonably priced, and they sell a wider range of weights than many other manufacturers (Wolverson don't do 40kg+, for instance). But I'm interested to check out a couple of the other options above which are new to me.