Agree about the reply about slots. The number of times we get airbourne in Europe with no slot and then run into congestion - what is that all about ?
Compared to Europe ATC, USA ATC is clearer, simpler and more practical IMHO. You seldom get multiple instructions - I could offer a suggestion as to why but won't - and the best bit - THEY CAN SEE WEATHER !
Also you don't get minutes of unintelligable French, not being sure when to break in, unless you are working Montreal that is