Irrelevant.  You guys are beating a dead horse.  Salamence goes Mixed or DD.  How that makes him uber is beyond me.  Luke goes Specs or SD.. Infernape goes Special Mix or Physical Mix... different sets have different checks.  If you switch your Gyarados / Salamence into Lucario (normally a good switch), you can be switching them into a Specs Hidden Power Rock.  I don't get what the point of this argument is.  You're whining that a pokemon has two very good sets that you can't seem to find a way to deal with...
I haven't heard people bitching about Dragonite yet on suspect.. since he obviously can run Mixed, DD, or Cleric DD all very well.  Uber.
		
		
	 
Well obviously unpredictability isn't the only reason he's been nominated for Uber. If that were the case, Smeargle would be an Uber! Obviously Lucario and Infernape both have the dominate set out of those two- looking at suspect stats, we can see that Lucario runs Swords Dance 87.2% of the time and is holding Specs 5.3% of the time. Obviously, Swords Dance is the dominant set, and once the surprise value of specs wears off, you have an underwhelming, easily manageable choiced attacker. Clearly, the swords dance set is the only viable one of the two.
As for Infernape, the vast majority of his sets are countered by the same pokemon, bulky waters. Physical Ape is only run 25.2% of the time (taking U-turn usage as the statistic). Unlike Specs Lucario, Physical Ape is, admittedly, pretty good in this metagame, but is worn down quickly by Life orb, all entry hazards, SS and spamming U-turn.
Dragonite, as we all know, is basically an inferior Salamence in every category except for support (for which I personally prefer Mence anyways, due to Intimidate and Wish, but that's somewhat irrelevant to the point I'm trying to make).
Yes, other Pokemon are unpredictable. But no other Pokemon has two unique sets, with entirely different counters, that both are extremely effective in the metagame and are both commonly used. Specs Lucario and Physical Ape and Dragonite in general will never be as dangerous as MixMence or DDMence, nor as prevalent.
tl;dr version: The difference between the above mentioned Pokemon and Salamence is that (1) Both of Salamence's set are used prevelantly because (2) both of them are extremely potent, or at least more potent that the aforementioned Pokemon.