I'm giving this place five stars and I don't even like the taste of M&M. M&M World is near if not on the top of my must-visit-when-in-Vegas list. The reason being - I do not approve of gambling (or any other get-rich-quick money-making schemes), clubs are not open until 10.30 (and do not get crowded until 12) and Vegas is not renowned for shopping (despite their claims of otherwise). That does not leave me with that many options for daytime activities.
As long as you don't get sucked into buying overpriced Made-in-China plastic toys and personalized coffee mugs and stickers, you'll enjoy the M&M World experience. The entire four-storey store is brightly colored - by the time I get to the second floor I was overwhelmed by the cute green / yellow / red / orange colors - It sure gives a new meaning to the term 'eye-candy'.
Good for kids and everyone else with Peter Pan syndrome. Present company included.