Miltank as a defender thoughts

I was just wondering what everyone's thoughts are on using Miltank as a defender?

I've hatched two of them with ZH/BS which is considered it's best defensive moveset?

I am asking this because I'd like to power one of them up to toss something different than the norm (ex. Vaporeon, Snorlax, Rhydon etc,. etc)

Thanks guys.