Yesterday I bought a couple of US Sunkist Moro Oranges to try. The local supermarket had just received a consignment of them.The experience was a disapointment. The rind and the inside flesh were deeply coloured and I thought this will be great. The flesh was dryish and the flavor was musty and unappealing. Like old socks.
I don't think my taste buds are off..well I hope not.

When are US grown Moros at their best? Presumably the two I tried were past their use by date.

As I have a young Moro in my garden I am enquiring as to what I should expect from the flavor. Does a Moro have the delightfully fresh flavor I would expect from an orange or does it have an aquired taste?

If the answer is the latter my Moro may end up in the compost.

Mostly grown in CA, and yes this is very late for Moro's. We usually see them in the stores around Christmas into Jan...

Don't judge citrus by grocery store California grown. I had the same experience here in Texas with California grown Moro oranges, lousy tasting. My home grown ones don't get the deep purple color California ones do but at least they taste nice even though they only have streaks of red color. Moro are good but I like Sanguinelli blood oranges better. Tarocco blood oranges are bigger but never get any red color here in SE Texas.

They grow fruit and produce for looks in California, not taste. Most are picked way too green and are tasteless.

Ive had mixed experiences with Moros too, this season was really bad I thought. I've had outstanding Moros and then Ive had really bad ones , similar to the way you decribe. The sunkist brand are not really good much past January, Moro is an early variety.

What I suspected. Selling them so late and so over ripe certainly doesn't do either Sunkist or the variety much good.
A bit like the much maligned Red Delicious apples imported into NZ. Floury and tasteless and yet every fruit looks beautiful.
And yet my home grown Red Delicious taste wonderful.

Well ...

All blood oranges are a more than 500 year old speciality of Sicily in Italy.

If you ever go there or can buy it all about in winter, then you know what delicious they can be ...

The taste is best describes with wild berries of the woods or very old red wine ...
Actually the Anthocyan is same flavonid in both ...

To get the highest quality you need low themperatures near or even below freeze and then you get very dark Sanguinelli, deep dark Maletese, dark Tarocco and absolute BLACK pulp of MORO, with deep red rind and juice deep red like blood.
The taste is just unbelievable and the health value is same ...

They are harvested some weeks after the freeze event for then the colour is fully developed and the longer you let them on tree the sweeter the taste will be.