My Fender Bandmaster (6L6) and my Delta Blues 210 (el84) have distinctly different sounds....I wouldn't say one is "better" than another. It just depends on what you want. Most of the time, you'll find 6L6's in higher wattage amps (e.g., 40 watts and higher) whereas EL84's are used alot in lower wattage amps (e.g., Blues Jr., 30 watt amps, etc.). A nice 50 watt El84 amp is the Peavey Classic 50.
I don't know that one tube is "better" than the other...it's just a matter of preference.
Guitars: 2003 and 2004 American series strats, Squier Classic Vibe 50's Strat, Squier Deluxe Strat.
Amps: Line 6 Spider IV 120, Vox AD50VT 212, and Peavey Transtube Bandit 112.
Pedals: Digitech Bad Monkey.