I have eaten at a lot of pizza places in Vegas - and I won't sit here and claim this is the best of the best in town - but it certainly shares the top spot with one or two others. Grimaldi's is absolutely delicious!!
First off - the crust. It's that thin NY style, with a great char flavor - it combines crispy and chewy in just the right way.
Secondly - the cheese/sauce - thin slices of buffalo mozzarella, with a delicious tangy/sweet red sauce makes for a combo that provides enough flavor that you really don't need any additional toppings - that being said...the toppings are delicious too!
I would recommend this place to anyone in town! One thing I would suggest is keep the additional toppings to a minimum - I never get more than two - because they start to take away from the amazing flavor the pizza already has. My personal combos are Pepperoni/Mushroom and Kalamata Olive/Mushroom - yummmmm :)
Service has always been great - even during the busy times.
Enjoy! Seriously...go. Now. Do it.