Varience is a key issue and this can be to some extent on how the wine has been treated and stored and as wine becomes much older the potential for variance is often greater. More alarmingly, on some occasions, individual bottles of the same wine from the same case can be markedly different. Undoubtedly, wine generally conserves better in large formats due to the air/liquid ratio i.e. there is a smaller amount of air between the cork and the wine. My own experience is that wine in large formats is more nuanced and the incidence of fault/problem is vastly reduced.