Fixed bounty is fair for all participant, but as i know many bounty with fixed allocation is not pay hunter higher than stakes based bounty.
that's why even i'm prefer to participate in stakes based bounty than fixed allocation
Actually i'm prefer stakes bounty because if we have more effort than the others, we'll receive more rewards.
But nowdays using too much effort on stakes sometimes ended dissapointedly because the token's price will ended bad in the exchanges.
So, i think it's better doing bounty paid with BTC right now