Meeraki MG21 as backup

[Manucha]

Hi Everyone, 

Could someone recommend good options for cellular data plans to be use as back up lines that will be compatible with MG21.  Is Google Fi a good choice.  I am moving away from Hologram due to high cost and devices getting disconnected randomly.

Thanks a bunch

[PhilipDAth]

If it is plugged into an MX and used as a backup-only link, it will use around 100MB of monthly traffic.