Any experience with the Coke-bottle KT88-ST (long life version)?

I am intrigued and attracted by their shape and color. Turned off by the price, different grades, and short warranties for supposedly "long life version". Warranties are 30-days to one year depending on the grade and cost.

Sophia Electric Coke-bottle KT88-ST Tubes (long life version)

I do not currently need tubes. These tube have always interested me and I am bored. Hence the post. But I would appreciate opinions on other KT88s. Some day I will need replacements.