For my 10 cents worth…
I have always found Panasonic HDD DVRs to be reliable and cost effective.
1. They are readily available from any electronics retailer.
2. You don’t pay a premium for "specialised offshore" equipment.
3. You can store in excess of one weeks data on HDD.
4. You can edit directly on the HDD and burn to DVD or flash (SD) memory.
5. You can obtain screen grabs directly.
I don’t work for or represent the company in any way but I’ve seen stuff offshore that is really over the top including Pioneer DVRs with Unix operating systems … for crying out loud how many Unix System Admins are ROV pilots (and I’m one myself)! 🙄