The Wyndham web site states:
For nearly two decades, Arthur's 27 has consistently been considered one of the most romantic restaurants in all of Central Florida. Enjoy five-star continental cuisine and panoramic views of firework displays and Downtown Disney. Winner of every major culinary award, Arthur's 27 offers unparalleled service and an unforgettable dining experience. For reservations call 407-827-3450. Evening or business attire suggested: jackets and ties are optional.
Policies:
Reservations Required
Dress Code
No Smoking Permitted
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That says to me that if you arrive wearing slacks and a collared shirt you'll be fine, but shorts and a t-shirt will get turned away. I think they'd prefer a sport coat, but as long as you're in slacks and a collared shirt you'll be fine.
That said, my choice would be Citrico's. You will want to wear slacks and a collared shirt for him and slacks and a blouse or sweater or dress for her, but it's well worth it! No jacket is expecetd or required, although when we dine there in the winter my DH usually wears a sport coat (not a suit!) and that fits in just as well. You will see suits there, but the majority people are in resort wear or business casual. It's very romantic, and we have found the service to be better than V&A's, the atmosphere elegant but not stuffy, and the food incredibly good!
Anne