Not got one and not used one but, if it was me, I reckon I'd go for the fermentasaurus or the fermzilla. As you say, they serve almost the exact same purpose but are a fraction of the price.
Having said that, I do have an ss brew tech bucket and love it so, it's a quality bit of kit.
Another point, if you were looking to go down the glycol cooling route I think the ss brew tech uni might be better suited. I'm not sure if you can get a similar set up for the fermentasaurus or fermzilla.