Has anyone made the jump to $uper High end and were disappointed?

+1 Wolf an everything you said cars and audio both! My used 2003 VW Passat is the single best purchase I've ever made and boutique shops run by enthusiasts make it cheap and easy to maintain. Similarly well selected and matched components will produce good sound at a variety of price points low and high.

The higher the price, the higher the expectation.

Nope if gears are chosen for SQ and not price, aesthetics ... 

Law of diminishing returns doesn't exist in my world.  If you want something SPECIAL,  it will reflect in price too.  IE:  it takes more engineering and cost to build a car with 170 mph than 100 mph top speed so price for a Porsche will exceed a Honda exponentially! 

Very interesting thread.  Value is so subjective, especially in this "sport" we've all chosen to indulge in.  And as stated, there are others that may be similar (cars, watches, homes, hell...friends and significant others if you really want to go there).

I love my two sets of $15-20K 845 SET monos and 300B PSET monos.  I also have a pre-amp in that price range.  I now wouldn't consider living in my audio world without some system at that level...it has absolutely been worth that investment for me, certainly compared to stuff costing half of those prices (which were no slouches). 

Would going up 50% in price, or doubling it, or more, make a valued difference?  I, for one, would love to hear $40-50K amps and pre-amps and speakers in a well-matched system in my home, and see how much more emotion they might deliver.  Of course it's incremental with diminishing marginal returns.  At some point you will determine it's not worth it, like in everything.  At some point there will reach a real limit, and you may even go backwards in actual performance.  I don't know if I would justify going to that level, but I'd sure like to know what's possible.

I waited 22 years to buy a Porsche from the first time I went to look at one and considered buying it until the day I drove one home.  I don't regret finally doing it one second any day of the week.  I wish I hadn't waited so long.  Worth it?  That question can only be answered by you, obviously.  Waiting that long also let me go big, which I did.  Also no regrets there.

I do like the OP's question, although it does appear that the audience to answer is small as others have stated.

When HiFi gear begin to cost in silly money, I lose interest in them and their reviews.  There is a simple reason if something like the 'Naim Statement' a pre and poweramp which costs at least £100,000.00 then in my mind if its not excellent its a failure.  So the reviews will be predictably glowing about the equipment, and so they should.  You will most probably read  silly statements like 'oh my god its like the quartet was playing in the same room!'  For the price of the equipment the quartet should be sitting on your lap!  However when you get serious equipment doing basic good  sonic hifi above its budget like the active ATC SCM19A or SCM40A then things for me get very interesting indeed because maybe in my life time the products are still reachable (perhaps a bank job here or there!)