Disclaimer: I've not eaten at Giada, so my opinion on that is second-hand.
To me they're apples and oranges a bit.
HHAGG - casual atmosphere, reasonable prices (for strip), HUGE portions - seriously, massive, no real view or ambiance to speak of
Giada - more formal atmosphere (casual attire still ok), higher price point, smaller portions, (potentially/table dependent) great view of strip/fountains etc.
I would highly recommend Hash House. I've heard mixed reviews regarding Giada.
I wish I could be more helpful, but I really think the experience you're looking for dictates this one as much as the food.