We use naval oranges during the greater part of the year when mandarins are not available here.
Mandarins are much more consistent than they were years ago; no poor ones for the last three or so years.
I remember when I was young that the navals were seedy and sometimes poor in flavor, but quality now seems uniformly good.

About once a year, some stores get the Sevilles, which we used to use to make marmalade. We are too lazy now, and use the good marmalade from Scotland.