If you are active duty or prior military and can use USAA - I would use them. We have been with them for years - my husband going on 25 years and me for 15.
There are distinct differences between the two insurances. HO-3 is "typical" home owners insurance. HO-8 is for older (75+ years) homes.
HO3 is the most popular form of homeowners policy written for insuring the
homes and property therein. HO3 policy covers most of the perils that may damage your dwelling.
HO8 is specially designed to protect the heritage and old dwellings. It offers protection against perils like- theft, riots, volcanic eruption and so forth. Normally, you can receive the actual cash value for your damages, ie. it'll replace the damaged property after deducting the depreciation costs.
Do you live in an old (over 75 years old) home?
Do you live in a recently renovated home?
Talk to the representatives. Get specifics on what you need covered, rebuilding costs, what you have on your property - tile, granite, lenoleum, etc. as each of these have a VERY different replacement cost. If you have 5 shower heads in the master bath - makes a BIG difference as well.