Della's was good, but probably not worth the walk we made from MGM.
If you're looking for it, you want to go into Mandalay Bay and walk just past the Michael Jackson One theater.
This is NOT a place to go if you're in a hurry, though. My girlfriend was starving, so she ordered a side and asked that it be brought out as soon as possible. It arrived maybe five minutes before the rest of our meals.
Our server was largely absent, so our water glasses were running very low before anyone came around for a refill.
I ordered the chicken and waffles. It was decent, but nothing mind-blowing. I think I would have liked the chicken to be crispy on the outside. It was pretty smooth and mild-tasting.
I might go back to Della's since the setting is nice and the food was pleasant, if not remarkable. Just make sure you have a lot of time because the servers won't really check on you.