AA won't let you route on one award on CX to India. You'd have to do it as two awards for more than 90k miles Etihad will be less miles. If you want to buy a paid ticket between HKG and BOM keep in mind they may not book your luggage all the way through on separate tickets. It's at the discretion of the agent. If that is important to you.
I agree with the above that in terms of flight experience whichever you can get a seat on is the one you go with. Make sure to check out the Pier at HKG. It was a beautiful space. And sign up for a free massage early as they book up fast. If going outbound, the new international terminal at LAX is stunning and the Qantas lounge is very nice. But I still prefer the lounges in HKG better.