I've tried the high-end Caspian caviars quite a few years ago when the prices were reasonable (when I was in my teens.) We had a family friend who sold us a few tins of Iranian caviar for relatively low prices (it was still $100 or so for 30g of Beluga IIRC) and we got to sample all Sevruga, Osetra (golden as well) and Beluga. I remember the taste being very distinctive - I wasn't a huge fan of it, but the novelty was there.

What they seem to serve in F cabins is not even close to Caspian caviar in taste or texture. It's saltier, has less of that earthy/rich flavour and is generally mushy. I take it simply because it's served, but I wouldn't mind it at all if airlines like LH, SQ or CX took it away and invested that money into improving their overall catering. I'd way prefer Balik salmon to it (I'm sad that CX took it away.)