Yup! These things, however, are hugely personal taste and system-dependent, which is why it's a fallacy to consider that there is any one 'best' valve of any type, Telefunken included.
What there is, however, are selected groups of valves, from certain manufacturers, which are of a higher quality overall than others (due to how they've been constructed), and among that you'll find ones that suit your ears and equipment best, as in my experience each has its own 'house sound' (sonic signature), which will either suit your ears and system or not.
In that respect, the worst thing you can do is use too many of the one type (from the same manufacturer), i.e. all Telefunken, as that way you'll get too much of the 'house Telefunken sound' [cool, clear, detailed, if a little matter-of-fact and 'soulless' - it's a German thing], when a bit of Mullard 'phatness' and warmth might be what's needed, especially with equipment prone to brightness.
You need to see valves as essentially tone controls, all with different 'flavours', so in order to get the best sound, it's about successfully marrying those flavours together, in order to create the right 'recipe' for YOU.
However, for the sake of amusement, if you want to kid on that there exists a universal 'best valve', ECC83 or otherwise, then carry on!
Marco.