This place is honestly one of the hidden gems in Las Vegas. The variety of frozen custard sundaes they have are all delicious depending on what toppings you prefer. They are all prepared over vanilla frozen custard unless you specify a different flavor. However, they only offer a handful of custard flavors a day as most people seem to prefer the toppings over vanilla.
My favorite would have to be the Banana Fudge Krumble (hot fudge, sliced bananas, and cookie krumble). The "krumble" is probably the finest ground Oreo cookie crumble imaginable--fine enough to choke on upon inhaling it (which I do quite frequently). :O Some sundaes are a bit on the sweet side i.e. the Butter Crunch (butterscotch and crunch). The "crunch" is what I believe to be finely cut pieces of butterscotch candy.
Note: They do NOT go easy on the fudge, caramel, or butterscotch, so you might want to request it not being too heavy or you may be eating several spoonfuls of the above mentioned.
Lastly, I personally have never been to Luv-it after dark by myself. It is not exactly in the best part of town considering it is walk-up window service and does often have several "interesting" passerbys... so bring a friend or two! Or maybe something to protect yourself with! ;) Order at the window, eat in the car, and lock your doors kids! Haha!