Yeah I guess people can argue that it is predictable but only beacause it has only one stage: locked (as opposed to an open centre which can spin both axles or just the one). An open centre can be unpredictable but not in normal driving situations so I guess it's the standard for that very reason.
But of all the people I have asked this is the general response, about half say go for it and the other say stay away, beware etc. So I'm going to try it to see what it's all about, personally I'm not sold to the idea but it's all I could get around here to replace the diff centre I blew. Following that a spare open centre will arrive and I'll probably use that instead.