Paul, you are referring to edge recording / using SD cards, yes? And are you asking about which cameras work the best or which flash / SD cards are the best?
There are basically two types of flash memory (although it is more complicated than this in reality) : Single-Level Cell (SLC) and Multi-Level Cell (MLC) devices. MLC devices can store more bits per cell and so are cheaper to manufacture for a specific memory capacity. They are less robust than SLC devices and have a much smaller number of write cycles before they start to fail. SLC cards have a much higher number of write cycles and are often advertised as "industrial-level" cards. But beware - some MLC cards are also advertised as industrial level, simply having a wider operating temperature range and other characteristics that involve more technical detail than I care to go into here. (Which is another way of saying "beyond my level of competence" !)
I have used SD cards in some low end domestic camera's/VMS's and have found that some will only recognise SanDisk cards or thumb drives (on the VMS) :-(
Discovered that recordign in Continuous mode is recomended, becauuse motion detection causes tte camera to create a file every time a MD video clip is generated, thus filling the SD cards in few hours.
Some brands (like Flir's Digimerge) offers 2 Format modes: SD Video and EXT3. In small capacity SD cards (2 GB) both can be used but in a 64GB SD card I could only format in SD Video format, causing that a D1@5 fps videoclip using more than 700 MB/hour.
Still testing, but be careful when proposing long storage (days) on SD cards!