What is the difference between Acuvue MOIST contact lenses and Acuvue OASYS lenses?
They are both 1-day lenses and both claim to retain moisture in the eyes. Acuvue Moist seems to be a new product. Is the difference just in the packaging or is one of them (one would assume the new one) better?

no, oasis is not a 1-day. oasys is a 2-week.
they are not similar lenses at all IMO.
oasys: 2-week, silicone, small diameter, miltiple base curves
moist: 1-day, plastic, large diameter, single base curve
MOIST is dailies lenses but oasys is a bi-weekly lenses. Oasys are better as it is silcone material.
Oasys is a 2-week lens, not a 1-day. I have used both and personally, the Oasys is a lot more comfortable and breathable.