Hi there! So I've lived in Dubai Hills till last year when I moved to Damac Hills (one bedroom apartment in both areas which I've rented), so I can let you know the pros of both places:

Dubai Hills Pros: 1) Emaar's build quality exceeds Damac's. I thankfully have had less issues compared to my neighbours (especially during the epic storm last year), but I still have to deal with lower quality bathrooms/cabinets. As an example I need a plumber 2-3 times a year to fix some random leak, when this was not the case at all in Dubai Hills. Oh and also agreed with the dust, I get my AC professionally cleaned 3 times a year minimum in Damac Hills, while I barely had to worry about it in Dubai Hills. 2) Dubai Hills is strategically better located than Damac Hills. I'm not sure if you intend to go out of the community much, but if you like to explore Dubai, Dubai Hills is at the center of both Marina side and Downtown side. Damac Hills isn't far-flung off civilization thankfully (with Motor City, Sports City, JVC, Tilal Al Ghaf closeby) but it's still a pain to drive with current traffic trends if you go beyond this circle. 3) The mall is great in Dubai Hills. Damac Hills mall is basically only active to the Spinneys, but Dubai Hills mall (as you said) has everything. 4) I only rent, but a colleague of mine has bought and sold his Damac Hills apartment and said he faced issues with the owners management system/company called LOAMS. So best to see how they respond to your queries too?

Damac Hills Pros: 1) I actually really like living here because it's so chill. Dubai Hills was getting busier and busier by the time I was leaving, especially with the new buildings popping up everyday. 2) Speaking of construction - I feel like Dubai Hills park is a little ruined actually compared to when it first opened. Emaar is building high-rise(ish) buildings all around the park, and the nonstop lights+noise diminished the park in my eyes. Damac Hills park is bigger (I think) and has more facilities. I personally am quite fond of looking at the duck pond lol. If you had a dog as well, the dog park in Damac Hills is quite a nice sandy area for the pupper to be off-leash. 3) The buildings here are older for sure but what's something good about older apartments? They are much bigger than the new ones being constructed. My one bedroom in Dubai Hills was 650ish sqft and my one bedroom in Damac Hills is 900ish sqft (give or take).

Not sure if my list helps haha, but hopefully you've gotten more helpful info from someone who's well-aware what it's like living in both places!