I vote for the Teannich but enjoyed all 4. Each had something different to offer.
I think the boldness of the cask strength won it for me though. Brute force and ignorance wins it for me
I too was surprised by the Fettercairn on how drinkable it was. However it does have a strange nose which I could not really get to grips with. Definitely not worth slating it for though.
The Rosebank had more flavour than I thought it would have too as I've had a Rosebank or too and found them light.
For me the Celtic nations was probably my least favourite. I strangley found that there was a conflict of tastes in the finish but that could have as much to do with a Guinness before hand than anything and I may be being a bit hard on it but I enjoyed it all the same.