I managed to get to both last year & found them both uniquely amazing.
Both are easily accesible by public transport, though HK a little further away (we stayed on site here). English was well known at both parks & in both cities.
Shanghai is HUGE! I'm talking HUGE!! If you go, split the park up into at least 2 days, and only do HALF the park in each day. Ex: we did the Adventure Isle side & watched the castle shows, parade & did a bit of Fantasyland. The next day we ROPE DROPPED Tron & other Tomorrowland stuff, moved onto Marvel, then onto the Fantasyland stuff we didnt hit the first day! We did 3 days total & managed to hit everything once & somethings multiple times. It takes too much time to cross the park to do otherwise!
Also for Shanghai, rope drop to the RIDE you want, the fp kiosk are a HOT FREAKING MESS first thing with lots of pushing. Head back to the kiosks AFTER a ride or two (and whatever you do do NOT buy fast passes from locals)
Hong Kong is MUCH smaller, it opens later & 2 of the lands open even later than that! But it is an incredible park! Grizzly Run, Mystic Manor, Festival of the Lion King & Wondrous Book are INSANELY AMAZING.
Hkdl's one downfall; the food prices, they're INSANE! Even the QS, bring in snacks/food & eat bfast before you go in to help with that!!