This really does seem to depend an awful lot on your choice of ingredients. This evening's offering (Tanqueray and Grouse) was a little disappointing, but with the Wine Society's 50% gin and Johnny Walker's Black label it works really well.
Made it with Bourbon (I don't know why, except that I was a bit tired), but it was sensational, and it will probably be even better with Rye. Complex, sophisticated, delicious, and incredibly boozy - this is what I imagined cocktails were supposed to be all about!