I used to have a loquat tree in my yard when I lived in Santa Monica. They always looked a lot better than they tasted. Invariably disappointing, they were juicy and very sweet, but had little flavor. And they have those big, honkin' pits inside. My feeling was always: no there there. We mostly let them drop, raked them up and dumped them in the compost heap.

How lucky you were! (though i know you don't think so).
I've actually had some really good loquats--they were mostly sweet, as you say, but they also had a lovely acidity to them too. The ones i got this weekend though sound exactly like what you had though--juicy bland sweetness, with a teeny bit of tannic pucker like you get from not-perfectly-ripe persimmons.