We have a Speidel fermentegg 600 liter. Works fine and one advantage compared to an ibc is the limited air space because of the shape. Also the two stainless taps, one higher than the other, are great for racking, filtering, etc. Cleaning is easy.
Don't know about the suggested 'special properties' because of the shape. And it's not cheap compared to an ibc. But it looks great :)
Cheers
Marin
IESSEL Cider