It will be AED 40-50 to/from GH to the Dubai Mall, which is not a huge amount in itself but can add up pretty quickly - think about whether the majority of the time will be spent at/around the hotel vs. other stuff in town.

I found Sheraton Grand Dubai excellent in terms of hardware and service, but did not get a chance to check out the pool and other facilities. I would skip the Four Points if not budget constrained. It is in a better location in terms of non-beach activities in town (i.e. very close to Dubai Mall)

If on-site F&B is important, also consider LM Dubai (but if you're not Plat, be sure to book the Royal Club rate).