In short: No problem.
Rockwell Automation will only provide support or warranty for the devices they sell.
While the A-B units are very high in price compared to commodity devices, the vibration and temperature specifications as well as the assured compatibility and lengthy availability are demanded by customers who have those conditions.
There is nothing technically unique about the A-B devices; they are ordinary FAT16 format ATA Flash and CompactFlash compliant devices.
I use SanDisk brand ATA Flash and CompactFlash devices very often for upload/download and data storage in PanelView and in ControlLogix, but have purchased a few over the years that did not work. CompactFlash compatibility is a more complex topic than you might think.
With PanelView Standard terminals, the ATA memory cards are only used for infrequent copies of files between the terminal and the card. This is the least critical way that the card could be used, and I would be comfortable using any ATA Flash device that had demonstrated compatibility.