I have the Ameda Lactoline which is a bit cheaper than the pump in style but still very good. It's the Asian name of the Ameda Purely Yours. You can purchase from Homecare Medical which has a shop in Causeway Bay. I think I paid about $1300.
http://www.homecare-medical.com/php/shop/shop.php?locat_id=3
Mothercare also have a double pump which is supposed to be good which is also cheaper than the pump in style.
Give some thought to how you are going to use your pump. Are you going to leave your pump at work? If so, weight of pump will not be an issue and one of the hospital grade rented ones will be best. If you're going to carry it home each day then will want something more lightweight. Double pumps will definitely save time because not only can you do two breasts at once, but many women find that stimulating both breasts at the same time yields more milk than doing both separately. And the faster you pump your milk, the faster you can get your work finished and get home to your baby!
It also depends on how much time you are going to be away from your baby. Do you live close enough to home to visit at lunchtime or have your baby visit you during a break? Then the top-grade pumps will be less necessary.
In the end I didn't use my double electric pump very much because I am always on the move in my job and often have had to pump in toilets, and didn't like the motor noise drawing attention to myself, plus my breaks are always rushed and it took a minute to set up the pumps. I ended up going to hand-expression, which is by far the cheapest method and all I had to carry was a plastic tub in my handbag!
But I am only working part-time and only after my babies have been six months old, so I have not been too worried about getting a high milk yield; it's more a matter of relieving discomfort. Nevertheless, it's worth remembering that human milk can be stored for up to 8 hours at room temperature (must be a bit less in HK summer), so if you are going to be home within a few hours then you don't need to bother with fridges and ice packs and cooler bags - just keep in your bag and put in the fridge when you get home!