I way too many tubes of the 6DJ8/ECC88 family, 6922/E88CC, 7308/E188CC types (except Telefunken -- I just couldn't bring myself to pay the price!). Very generally speaking, there is a fairly consistent "house sound" to Siemens (sometimes labeled RCA), Philips Holland Heerlen factory, sold under various names), Amperex (Hicksville, NY), and Mullard.
"Best" is a matter of taste and synergy with your equipment. So "try 'em all." Buy "slightly used" tubes and have a party.
I change tubes from time to time. Which is best? Whatever I have in the pre-amp at that moment.
The Tubeworld web site has a great deal of information and discussion of one type versus another. The tubes are extremely well selected, but it is reflected in the prices. Tubemonger has quality tubes at good prices. I won't make any negative comments here.
As far as price goes, my view now is that it can be cheaper in the long run to buy a primo pair of tubes from a reputable dealer, at a high price, than it is to buy several pair of the same type on eBay, chasing that elusive bargain. Just my opinion, based on experience learning the hard way.