Well it was only going to be so long until this opinion splitting conundrum popped up, wasn't it?
If you're asking this question then you are one of two things; either obsessed by the details ( come on in, the waters warm ) or monumentally lonely ( ha ha, rofl-copter...oh god ). Whichever it is, we'll try and help... As long as it's the first one.
So we better start by explaining exactly what the difference between the two actually is. It's all to do with how a pedal deals with your dry guitar signal, when said pedal, is turned OFF. All pedals pass your signal through their circuit when turned ON and a buffered style circuit continues to do so, even when the pedal is off. This gives it a little nudge along the way. A true bypass pedal, removes the signal from the circuit, creating a "clean" signal path through the pedal when it is disengaged. Think of it as just your guitar cable going through the pedal, instead of in to it.
Well if its that simple then why do so many hairy people called Mark, get hung up on it? Well this is where it gets a little more complicated...
Firstly, Mark's are almost impossible to please. That's a given.
Secondly, both styles of pedal have their benefits. True bypass will retain more of the original signal's qualities ( yay! ), as long as you don't have too many of them chained together ( boo! ). Buffered pedals will help "boost" a weakened signal back up ( like the kind you'd get if you have too many of those pesky true bypass pedals chained together ) back up to where it should be ( double yay!! )
Hang on, so you need both!?
BINGO! If you're going to have a decent sized pedalboard ( and only a total loser or worse, an acoustic guitar player, wouldn't ) then you need both. The true bypass pedals will keep your dry signal as original as they can until the occasional buffered pedal gives it the "leg up" your signal needs. Both types are incredibly useful and there simply isn't a "better style".
Pedals are a bit like pizza in this regard. They are all good. Apart from the ones with tuna on them. Obviously.
Ultimately everything on your pedalboard will affect your tone, from the order of the pedals, to the power supply used, to the length of cable in play but hopefully this quick rundown can help you navigate this murkiest of subjects. Try putting your favourite fuzz before and after that buffered pedal. Experiment! If nothing else, a solid knowledge of the "buffered vs true bypass" question, will make you infinitely more attractive to possible mates. Probably.
Take care!
Louise
