I ownn a Del Tin 2160.
http://www.deltin.net/2160hi.jpg It has rings, anulets and is not simetrical.
I have found that it allows me to train with much more confidence of not getting my hands hurt, when performing certain techniques.
There are several examples of what I'm saying. I the one I preffer to illustrate this is that my fingeres are really well protected when performing a -not so perfect- zwerchhau against overhaus.
My only complain to this particular model is that it feels heavy (due to the extra metal of the rings) and that the handle is a little short. But training rapidly overcomes these "flaws".
But overall I'm really happy with it. I would buy this model again.
Francisco
ARMA Lansing