[MajorDave]

$45 per year. Comparable in coverage but less top dollar limit.

MidMoUmp has a blog that compares the two.

Sort of an Apples vs Oranges thing as they both have more than just insurance for the money.

EDIT: I went ahead and copied info from MidMoUmp's blogspot. He also compares ASA and NFHS insurance. His final statement on the blog is; "Clear as Mud?"

NASO Insurance
Cost: $94.00 annually included in membership fee
General Liability: $3,000,000 per occurrence with a $4,000,000 aggregate
Errors and Omissions: $50,000 per occurrence (as an umpire or assigner)
Heart or Circulatory Malfunction Death Benefit: $5,000
Assault Protection: up to $3,000 in attorney fees on a 60/40 basis (you pay the 40% until the plan has paid out $3,000).
Game-fee-replacement insurance: up to $100 for each game lost within 21 days after the injury up to $500 total.
Accident medical plan: None
For an additional fee NASO provides Optional Game Fee Loss Insurance for injuries not related to assault. This plan pays up to $1,000 to $2,000 depending on the plan selected.Covers all sports official activities

ABUA Insurance
Cost: $45.00 annually included in membership fee
General liability: $1,000,000 limit
Errors and Omissions: None
Heart and Circulatory Malfunction Death Benefit: None
Assault Protection: None
Accident medical plan: $100,000
Game-fee-replacement insurance: $2,000 maximum benefit
Covers while working any level of amateur baseball AND softball