"Although not strictly a food forum" ...

R U from another planet ?
for 4 people $900 is a high budget for Cantonese food without abalone or shark's fin !
Summer Palace at the Island Shang is worth going to for the ambiance and quality of food.
If you do want the abalone and/or shark's fin and your budget is 3.5K than I would suggest a less upmarket place
like Tsui Hang Village rest where the food is excellent but ambiance less so ... try their cha sui - best in HK !