I've been using MO in my ESB trying to create something like Old Speckled Hen using S-04 and don't really get biscuit. Before trying for OSH my ESB tasted like unsweetened tea.
Soon I'll be searching for a liquid British yeast that's versatile for an ESB, IPA, old ale, and barleywine. Something I'd use often enough to keep it going a while. S-04 just hasn't made a good ESB for me it seems. I'll be brewing one more time trying for OSH on Monday with it though.