They're the only home routers I've ever owned which aren't constantly failing in some way. It's a shame they're only really available in Germany (and I guess Austria).
Can confirm they are in use down here in Australia. I know someone who just upgraded their 7490 to a 7590 due to compatibility changes with our National Broadband Network (enablement of SOS-ROC).
I brought mine over from the UK for use here in Germany and just upgraded. Sadly it seems their extenders are only available with EU plugs so I'll have to send some back for my parents, they really are that hassle free that it's worth the effort.
I was sufficiently pleased by the FRITZ!Box that I bought a 2nd one to extend the wifi in my home - very easy to do with the fritz devices.
[1] https://www.zen.co.uk/broadband/broadband-router