I found Glenlivet 12 to be one of the smoothest whiskies I've had. Though, I've learned people's impressions of whisky changes day to day and bottle to bottle.... mine certainly does. Ralfy reviewed Glenfiddich 12 and didn't have much good to say about it. Then a few years later he reviewed it again and loved it. So, I take impressions with a wee grain of salt.
As far as adding water... sometimes it seems to help, other times not. Sometimes it just adds a water taste and does nothing about the burn. To me personally, at best, its more trouble than its worth. But that's me.
I sip my whisky neat. If my sip is big enough that any made it more than halfway down my throat, then the sip was too big. Just enough to coat my tongue will do. Anymore than that is a waste that I didn't get to taste. Small sips like that also helps with the burn. Also, the more sips you take, the more it seems to smooth out and burn less.