I thought I'd give some impressions after getting to spend some time with a couple of full drams given that the opportunity window to buy seems to be closing due to stock being bought - and there wasn't much to begin with anyway.
The bottle does say Wine cask-matured, but the small print says 6yrs in bourbon cask, the rest in wine casks. In taste I would say the bourbon side conrtibutes about 3/5ths of the flavour. You get that berry flavour that comes from wine finishes but without the cherryaid dryness or grip. The vanilla is there as is the telltale Bowmore smoke and floral notes, and they play off against the berry and bourbon influances. There is your complexity. The 53% abv means you can pick the strength that you want, and that and the NCF means the flavour comes out loud and clear.
I think this is simply a better Bowmore than others I've tried. If you like Bowmore (like me) you'll probably like this more unless the wine influance is something you want to avoid at all costs. This influance is not done with a heavy hand to overbalance, but with enough strength to provide a counterpoint to the other flavours. If you do not like Bowmore you may like this, but may not think much of the value of the bottle my hunch says.
Hope this helps.
Edit: Aha! There seems to be more bottles in stores according to the LCBO on-line inventory. Good news - not such a time crunch for decision making. I also made an earlier mistake in that it is the Summerhill Tasting Tower not the Bayveiw/Sheppard one that has the Bowmore Wine Cask-Matured to try. Sorry for any confusion this may have caused.
