a non-o starts as a 90 day visa and 1 yr extensions, you require 800k in Thailand bank for the extension (or the original 90 day if obtained in country.)
Can be obtained from home or in country.
An OA is a 1 yr visa obtained from your home country only.
Using proof of funds only from home.
It requires health insurance
Police check
Medical
It allows multiple entry and can be be stretched to almost 2 years as you get 1yr on each entry. *as long as you have proof of insurance.