The best ( clean, efficient, hi-tech) airports and airport lounges are in Asia. End of discussion.
Kuala Lumpur, Hong Kong, Bangkok, Doha, Singapore instantly are way ahead.
Generally speaking yes.
I lived in KL, SIN and BKK and frequently transited through HKG. Just recently spent some time in the new lounge @ HKIA, the new Pier First Class lounge - amazing, especially the food (although I admit, the lounge experience can be quite 'superficial' in many ways).
The lounges at KLIA have seen their better days I am told (they are generally OK for me, and of course beat any UA Club). As for SIN lounges, depends if you are on SQ or *A flight, as not all *A Golds have access to the SQ Business lounge (which is nicer and has great food).
As for the US, I am quite OK with the AA Flagship Lounge @ JFK (the first class lounge, not the business class one - huge difference), and in the UK, the BA Terraces First @ LHR is fine as well (nice views and a separate terrace-like seating area).
The one lounge that surprised me positively, mostly because I did not read about it ahead of time and did not know what to expect, was the Qantas First Class Lounge @ SYD - I wanted to stay there for ever
: excellent food, great service, beautiful views, etc.
As for our adopted continent, the *A Gold lounge @ EZE is nice aesthetically, but lacks the food and the service you would get in Asia. I accept that, and enjoy what I can. Same for the Iberia/Lan/AA lounge @ EZE. The old *A Gold @ GRU was horrible (and I remember the old UA lounge @ EZEZ equally bad), but I heard it got renovated. The new Avianca Lounge in BOG is quite an improvement, but again, the lack of good food and service takes away from the otherwise good hard product.