My brother in law read somewhere that because SPMLs are prepared individually they tend to taste better. He thought he would be clever and ordered the Kosher special meal on a longhaul (he is not Jewish). But he neglected to check the date - it was Passover. So his meal was a plate of matzoh bread and some grapes
I can't recall if he experienced a sudden conversion or just went hungry
I ordered kosher special meals on domestic Y flights a few times (back when meals were served on domestic) and they truly were tasty. Never ended up with the Passover meal though. The only difficulty was getting through the industrial strength plastic wrap without metal cutlery. I had to saw through it with my car keys.
Kosher meals are prepared separately in a Toronto synagogue while the other special meals are made by the regular caterer.
These days I order gluten intolerant meals but the bread product is usually a bone dry tasteless corn bread I never finish.