Ive used mine as a fermentor... It's ok, not too hard to keep it clean. I just take the spigot out and soak it in some oxyclean, then hit it with sanitizer before use.
The big draw back is not having a bottling bucket when your pipeline is full. I've managed to get myself into a predicament where I have two carboys full (one ready to bottle, one that needs a little longer) and I have a beer fermenting in my bottling bucket. This is a big problem, because my carboy space is all used up and I don't have any way of bottling without transfering my beer to an intermediate container...
Strongly suggest having a designated bottling bucket, unless you are just going to do one brew at a time.
Edit: Also the spigot tends to leak a little bit. It's not really a problem, but when fermentation is going on you might have a few drops of sticky wort to clean up.