I got one of these back when they first came out and have done a few batches in it. I don't think I've found the best way to use it yet, but I have found a flavor difference using that vs using my carboys (and not necessarily positive).
One thing that I noticed is that if you use the ball on the bottom while fermenting, you can end up with the yeast down in the ball fermenting and not sitting at the same temperature as the rest of the conical since the thermowell is up in the main body of the thing. I was using a heating pad strapped to the side with a controller, which isn't the best way to control the temp. I need to rebuild my ferment chamber to put the whole thing into it so that the temp is more stable across the whole fermentor.
Using the conical is certainly more convenient than using carboys. Dropping trub, harvesting yeast, all that stuff seems to work well enough.
Overall, my opinion is still out. I think I need to get the chamber finished and do some more batches to figure out what exactly the best method is to use it. There is a pretty long thread on it on homebrewtalk.com.
http://www.homebrewtalk.com/f14/fastfer ... er-478906/[Edit - Mod edited so this post shows up]
