I use/used bottling buckets for fermenting exclusively for years...... They work great. I bought a couple SS buckets on first release for the cheaper price. I liked them and bought two more for a more expensive price a couple months later. I am happy with them. Glad I bought them. I still use bottling buckets too if I have more than 4 beers going.
Are they "worth it"???? If it is not going to "put you out" to buy them..... sure.
To me I am happy I bought them. Now, I would not spend that money on the SS buckets instead of temperature control, or other aspects of brewing if it was a choice. But, I have everything else I need, and I had some money to spend on them.
They are easier to clean, they are obviously stainless instead of plastic which is a plus. The conical bottom drops sediment out better than it seemed to just settling in a bucket. The only thing that I still worry about with the SS bucket is the ball lock spigot..... I am really paranoid about cleaning it. PBW soak after every batch, starsan soak after and before every batch. Boil it every 3 batches or so...... I don't like things I cannot see inside of when it comes to cleaning/sanitizing.
Now, I would DEFINITELY buy 2-3 SS buckets before I would ever buy any of the more expensive stainless conical fermenters .... Almost bought one or two of those at one point - really glad I did not now that these came out.