Perhaps worth saying as well, please do not buy a nice whiskey, and ask for coke mixed in. If you tried that in Scotland or Ireland, they would at best refuse you.
The "ppm", in the Scotch context, is for the amount of peat phenols, which is essentially a peatiness metric, and it is recently a competition metric, for some reason, between at least a few distillers ( http://blog.thewhiskyexchange.com/2009/03/bruichladdich-octo... as an example article but you can just google scotch ppm and get a ton of articles ).
I haven't had the Octomore but the Supernova is not that great in my opinion. It was interesting to taste a Scotch intentionally that peaty, but I'd consider it more of a novelty than a great taste improvement. That said taste is an amazing thing, so it might be precisely your cup of tea.
In terms of enjoyable smokiness I'm with you on the Ardberg, but in terms of the crazy +peatiness competition in Scotches, it isn't the winner.
But my absolute favorite is Port Charlotte, which is produced by Bruichladdich. (I'm not enough of a connoiseur to appreciate the differences among PC 5, 6 and 7.) It's the most intense and flavorful scotch I've ever had, but not very rough. Pretty smoky too. Unfortunately it's kind of expensive and kind of hard to find.
As a condition of this award, we agree to pay a yearly ground rent in the sum of one dram of Laphroaig, to be claimed in person at the distillery. You’ll understand we’re not offering heritable ownership or any right to cut peat, farm sheep or extract minerals from the plot - far better to take up your right to a warming measure of Laphroaig.
Upon the Leaseholder’s arrival at Laphroaig we undertake to provide a map, with adequate directions for locating the PLOT, and suitable protective clothing against Islay’s rugged weather and eccentric wildlife.
I've only used it to put infuse some smokey herbal flavor in cooking, its way too smokey for me.