Seems to me that every argument against multiwire branch circuits stems from either the improper installation or improper modification of the circuit.
I troubleshoot lots of branch circuit problems that are neutral related. They are usually caused by some numbskull stuffing 6-#12 into a red wirenut or something like that.
I have NEVER run into a case of a problem caused because there wasn't a dedicated neutral run for each circuit.
This stuff of installing the circuit so a DIY can work on it is not shared by any other trades or manufacturers. (Look under the hood of your truck, for instance). A professional should be called out if the DIY lacks the competence to work on the system.
[This message has been edited by electure (edited 05-14-2006).]
