The importance of register

The text is talking about Gazprom and its European customers. In a section dealing with why the Czechs pay such a high price, compared to the British or the Dutch, is this sentence:

Вaжнeйший чeшский постaвщик гaзa при этом являeтся eвропeйским уникумом: он полностью нaходится в чaстных рукaх.

Now, уникум (unicum) is a word I'm not so familiar with that I don't feel I should check that my instinctive "unique, yeah?" reaction is right (after all, there are plenty of Russian words that were clearly borrowed and which don't mean what you might think, like аккурат (akkurat) which means "punctual" or "neat, tidy"). And here's where the importance of register comes in. This is its set of meanings:

general: unique; unicum; the Arabian bird; best thing since sliced bread; one of a kind; world-beater; unique object; one-off
religious: unicum (Latin for "the only one")
slang: bee's knees; the bee's knees

But

This largest Czech gas supplier is, by the way, the European bee's knees: it is completely privately owned

No.

And

This largest Czech gas supplier is, by the way, a European world beater: it is completely privately owned

Also no.

And as for

This largest Czech gas supplier is, by the way, the European best thing since sliced bread: it is completely privately owned

Not just no, but hell no.

For that matter

This largest Czech gas supplier is, by the way, the European Arabian bird: it is completely privately owned

is also no good, though it's better than the others. Instead, you're going to have to go with something like

This largest Czech gas supplier is, by the way, a rarity among European companies: it is completely privately owned.