IMO, LOTS more flavor(s) to be had with Scotch, but they just price the stuff so ridiculously, that they keep people OUT. The wide range of flavors also really throws people. I've had women tell me they hate it, and can't stand the stuff, only to find out they had some doosh either playing pretentious knob, or pranking her with a peat bomb, and then thinking it's funny when she gags. I get them the nicest tamest intro, Glenlivet 12, and they can't believe both types are scotch. Someone, somewhere, had the opportunity to introduce them to all that scotch has to offer, and they chose to be a jerk about it for whatever reason, instead of easing them into it and explaining what makes/causes things to be wildly different.
Tastes are tastes, and people who think theirs is the correct one, without taking into account what others may enjoy, aren't the people I want to hang out with. I have a friend who brews beer with his neighbors. They ALL enjoy IPA's, and without fail, ALWAYS want me to try theirs, and then proceed to tell me I don't know my asshole from my elbow when I tell them I can't stand IPA's, and I "just haven't tried theirs yet". No, it's not my thing - AT ALL. Stouts, porters, bocks, any dark beer is for me, no matter the time of year, and that's just what I enjoy, so stop trying to force me to love IPA's. I'm doing you a favor, and leaving more for you to drink, so how about taking a cue, and pointing out some things I might like, instead of forcing your tasting opinions down my throat? LOL
You'll really enjoy Scotch, other than the (generally) lower proof. The wild differences in areas can be further explored based on ingredients, aging, and what they're stored in. I find it fascinating, but I can also see how someone can find it overwhelming, and want to stick to "simple". Like beer, whatever floats your boat. The point is to enjoy what you're drinking, and if you're also with friends, all the better.
I think you'll like the 15, but I find the 12 to be the better one of those two, and the 18 to be a waste of money. None are overwhelming, but then again, none are anything other than easily available and drinkable. Glenfiddich is a nice improvement over Glenlivet, IMO, but again, individual tastes... ? Tomatin is another that should be easy to find, easier on the wallet, and pretty decent selection to fit what you like in taste. In my area, I can get more than a few different little tasters, which has helped. Once you find something you like, the internet can help you find something similar to branch out with, and you can go from there.
Pinkies up!