Spec's Liquor here in Houston carries Sean Michael's Macallan, a 12 yo, 16 yo, and 18 yo. The only tasting I've done is in Spec's where you get a sample in a little plastic cup and this was a 16 yo not the 18 yo, so take this for what it's worth. What I remember is that it was not bad but not really great, either (it did not impress me enough to want to buy one). The really noticeable feature of this Macallan was that it significantly lacked the sherry flavor which typically characterizes a Macallan (even more so than a FO). I do recall a hint of vanilla, I assume from some bourbon cask aging (the young lady serving the samples didn't have a clue about such details). It was a nice smooth, mellow dram, but not much depth or complexity. If you're interested in a Macallan without the strong sherry influence, you might give it a try.
As a price comparison, Spec's sells the 18 yo for $117, with a Spec's membership discount of $25.
Regards -- Yellowjacket