Hi: Please weigh-in on this a friend suggested mixing Dove dish soap with drywall joint compound. This, he's heard, will make a smooth, no-sand finish. Any truth to this? Thanks.

Hi all, Okay, so which is better: horsehair plaster over lath, or drywall? I had always assumed modern drywall was a superior product. But recently I've heard a few people talking about the horsehair plaster walls in their old houses like they were a nice feature, like old woodwork or something. Are these people lunatics or do they know something I don't? Part of the reason I'm asking has to do with insulation. Let's say I was going to insulate behind a given wall. Would it be better to: a. tear down the plaster and lath, insulate with something like fiberglass batting, and then put up drywall; or b. try and preserve the plaster and lath by renting a blower and blowing in the insulation behind the walls? Let's pretend that for whatever room being worked on, it doesn't matter how much time it takes or how much mess is created. I just want to know what the best final product would be. Thanks for any thoughts/advice. - Chris