"Better" is a bit of a subjective term, but here are a few answers for you:
The Trails: More of a family neighborhood located adjacent to all of Mammoth's schools, including Cerro Coso college. This community is also popular because of its proximity to the skate park and new Trails End community park.
Mammoth Knolls: Has a reputation for remaining "non-transient" by being very vocal against single family home rentals on a nightly basis. This neighborhood also has CCR's prohibiting nightly rentals.
Old Mammoth: Is popular among Mammoth locals.
Luxury Neighborhoods: Neighborhoods such as Starwood, Grayhawk, Snowcreek Ranch, The Bluffs, Juniper Ridge tend to have a very high level of owner/2nd owner occupancies.
There are a few others, but these are neighborhoods I would consider "Better"neighborhoods with fewer tenants.