Is there a perceived Leader? This probably cannot be answered on an objective basis. Whomever you ask may select one over another for various reasons. One might prefer Gordon&Macphail, because they are amon the oldest being around. I dislike their practice of filtration and colouring, though, and often find the quality of their products lacking. Others might think Signatory to be the leader, but I believe their price/performance is not very good, and that you pay to much for name and packaging. Then some might say it's Cadenheads, but, while they have some outstanding bottlings, others are just so-so, and I generally dislike their selling policies. Some prefer Murray McDavid, but I hated all bottlings I tried so far. Cooper's Choice is among my favourites, offering outstanding price/performance. Blackadder has a quite diversified portfolio. My current leader, however, are the Hart Brothers, offering highly interesting Malts of outstanding quality at adequate prices, and generally hit "my" taste. But, to repeat, this is just personal (as it must be).