I’ve used both the Omniscan FS on an ROV, and the Omniscan SS on a BlueBoat!
Image quality is pretty impressive, and if your vehicle has information on its position, SonarView illustrates you moving around the sonar “map” of returns as the mission progresses.
I’d note that Cerulean Sonar’s products connect to SonarView - this can run onboard a vehicle like an AUV, but within BlueOS running on a Raspberry Pi. There is no direct integration with Ardupilot…
ArduSub does not support things like control surfaces that may be required on your AUV - but don’t let that discourage you! In general, setting it up for use as an AUV is possible, and may require some Lua scripts for your intended funcitonality…