There are two key features that I find make it a unique experience. First is its lack of a dice or other 'introduced' randomising element - the initial cards dealt do obviously randomise things but there is not generally such a thing as a good hand or a bad hand - it just relies on how the players choose to act to randomise things. Second is the lack of turns. The each round just kicks of and turns into an increasing melee until someone gets a set.
One thing that is also interesting is that you might think there are no good or bad strategies to this game, other than the blindingly obvious. Yet in spite of this I have found that the same people tend to keep winning while others (me) don't do so well. Luckily this is not extreme and any one game could go to anybody but I was surprised that there appear to be good players and bad players. Be that as it may it is still a cracking game.
The only reason we finished playing (at 3.15 in the morning!) was just in case we woke our grandparents upstairs. It's fast, it's loud and best of all, it's fun.