I haven't had many slivovitzes; out here in the west they're not common. However, in my experience, the best (maybe the only really good one) is the Jelinek 10-year old 100p-poof one. But I wouldn't mind trying some othes.
The Hungarian one we get at Trader Joe's; my wife puts some in her chocolate cakes.
The one from Yugoslavia will take out your insides; we used to drink it at Balkan dance parties.
Tasted Slivovotz twice in my youth and the bad taste still lingers in my mind. My grandfather z"l used to make Havdala on it and I remember us kids being thrilled weekly when he attempted to extinguish the candle and the entire plate would go up in flames. Best use for it. Zvi